The strategic advantage won by Rome in the First Punic War-of being the most potent naval force in the western Mediterranean-proved to be decisive in the outcome of the Second Punic War, from 218 to 201 BC. It was during the second war that Carthage's brilliant general Hannibal famously led his army and a contingent of elephants from his base in Spain across the Ebro River into Gaul, over the Alps, and into Italy, where he marauded victoriously throughout the Italian countryside for over a decade in what proved to be a fruitless bid to trigger local insurrection against Roman rule. In the end Hannibal was unable to sustain his supply lines without naval replenishment and was ultimately defeated on the banks of the Metaurus River in 207 BC, when reinforcement troops traveling overland under his brother Hasdrubal failed to arrive in time. Indeed, it was Rome's naval superiority that had compelled Hannibal to attempt the treacherous overland invasion of Italy in the first place. Had Hannibal been able to go "by the sea, he would not have lost thirty-three thousand out of the sixty thousand veteran soldiers with whom he started," concluded Captain A. T. Mahan in his classic The Influence of Sea Power upon History The Influence of Sea Power upon History. Sea-power superiority also delivered Rome the means to counterattack Carthage. Through the naval supply buildup of a formidable army base in northern Spain, it besieged and finally took Carthage's Spanish stronghold at Cartagena ("New Carthage"), and then forced Carthage's surrender in 202 BC through attacks on its North African homeland across the Mediterranean.
The first two Punic Wars transformed the trajectory of Roman history. The conversion of the entire western Mediterranean basin into an unchallenged Roman lake brought Rome its first taste of the fruits of ruling a provincial empire and propelled its rise as one of history's great powers. All the grain wealth of Sicily, the mineral deposits of southern Spain, the tin, silver, and other resources that moved from the Atlantic through the Pillars of Hercules, and slave manpower from defeated populations came into Roman hands. Gradually, Rome ceased striving for basic self-sufficiency from its low-yielding home soils and began to rely on shipments of imported grain for its daily bread. Large estate owners abandoned drainage projects to reclaim marginal cropland in favor of producing higher-value-added, tradable luxuries like olives, wine, and livestock, often with slave labor. Class tensions polarized as wealth became concentrated in fewer hands, while individual military commanders compensated by advancing the interests of free commoners, who increasingly served as their professional troops.
Initially, Rome took uneasily to its changing political cultural identity as a hegemonic maritime power. Only gradually during the course of the second century BC did it accept the inexorable demands of its success to extend its dominance over the eastern Mediterranean as well. Nevertheless, whenever possible, it exerted its weighty influence indirectly through the soft power of financing trade and being the largest import market, while leaving naval patrol duties in the east to maritime allies like Rhodes and Pergamum. As late as 100 BC, Rome had scaled back its fleet in the eastern Mediterranean to skeletal size.
All that changed dramatically during the first century BC when pirates began to exploit Rome's minimal naval presence. The largest group of buccaneers, headquartered in Cilicia on Asia Minor's rugged southern coast, possessed more than 1,000 ships and a formidable arsenal, and was ruled by a well-organized, hierarchical command. By 70 BC they had become an intolerable nuisance by interfering with vital grain shipments to Rome and by brazenly raiding coastal highways as far away as Italy and kidnapping prominent Roman citizens for ransom. One famous hostage was the young Julius Caesar, who was seized while on a ship bound from Rome to Rhodes, where he was to study law. During his captivity Caesar amicably suggested to his captors that due to his importance, they should double their initial ransom demand-which they readily did-and promised, with equal geniality, that after his release he would return to crucify each and every one of them. In fact, as soon as he was freed, he raised a fleet in Miletus and killed as many as he was able to catch, though as a reward for their decent treatment of him he allowed their throats to be slit before nailing them to the cross.
Gripped by a sense of national crisis at the threat to its food supply, Rome's Senate finally acted. In 67 BC it commissioned General Pompey to rid the Mediterranean of the pirate menace and invested him with almost unlimited power to accomplish it. In one of the most spectacularly successful naval operations in history, Pompey amassed a force of 500 ships and 120,000 marines and launched a methodical, sector-by-sector sweep of pirate enclaves eastward from Gibraltar. In less than three months, all the pirates were defeated and the buccaneer capital in Cilicia was besieged into submission.
Pompey did not stop there, however. Without authorization from the Senate, he sailed his formidable fleet to the Near East, where he brought Syria, Judaea, and the cities of Antioch and Jerusalem under Roman rule. He returned to Rome in 62 BC as a conquering hero with fearful power, and entered a ruling triumvirate with Caesar and Crassus. Pompey's naval operations revived Roman sea power and organized it into a permanent naval force. Thereafter, it always would be a crucial component of Rome's ability to wage war and enforce its will on others. At first, however, it was turned inward upon itself in two decades of bloody civil wars that were ignited on January 11, 49 BC, when Caesar and his army marched across the muddy little Rubicon in northern Italy, which violated the republic's forbidden boundary line, and amounted to an attempted coup d'etat. The ensuing civil war between Caesar and Pompey was fought across the breadth of the entire Mediterranean from Spain to Egypt, with Caesar's breakout from Pompey's blockade in the Adriatic playing a major role in his ultimate triumph prior to Pompey's assassination in Egypt. When Caesar, now dictator for life, himself was murdered at the Senate in Rome on March 15, 44 BC, civil war erupted anew.
Fittingly, the final, decisive battle that ended the civil wars and inaugurated the imperial era was fought at sea, in 31 BC, off the Actium promontory near the Gulf of Corinth in Greece. On one side was the allied force of Caesar's leading general, Mark Antony, and his lover, Egyptian queen Cleopatra. On the other side was Octavian, later honored by the Senate with the supreme title Augustus Caesar, the young grandnephew and adopted son of Caesar. In command of Octavian's fleet was his brilliant military commander, lifelong right-hand man, and civic colossus of the Roman Empire in his own right, Marcus Agrippa.
To try to offset his inferiority at sea, Octavian had raised a new navy of 370 ships. Recognizing that his enemy's more-expert crews and nimbler, more-lethal vessels rendered futile any attacks based on the conventional tactic of ramming, Agrippa, in a stroke of genius reminiscent of Rome's design innovation of the spiked gangplank in the First Punic War, armed the ships with a new weapon he conceived: a catapult that fired arrows leashed to a rope and tipped with an iron-clawed grapnel that enabled his marines to clutch onto enemy galleys from much farther range than the conventional, hand-thrown grapnel, and pull themselves in by windlasses for hand-to-hand combat. With the help of the catapult grapnel, Agrippa's fleet won decisive battles off Sicily in 36 BC that reversed Octavian's waning fortunes and went on to win control of the sea war on the Mediterranean. By the time of Actium, he held enough strategic bases to interdict Egypt's grain supply freighters, and thus slowly starve Antony's huge military forces, including its Actium fleet, into submission. At the battle itself, Agrippa enjoyed a numerical warship advantage of 400 to 230. Before the day had ended, Cleopatra and Antony had fled for Egypt, where, a year later, they committed suicide, while Octavian's Rome seized direct possession of the Mediterranean's last nominally independent great state and with it the prize of the rich Nile granary.
Octavian acquired the title of Emperor Augustus and prudently consolidated his power by, among other actions, establishing a well-organized, permanent professional navy to police the Mediterranean. Over the next 200 years of the Pax Romana, Rome's empire was extended from the Atlantic to the Persian Gulf, from North Africa to the northern British Isles, and from central Europe through the Balkans. To secure the frontier against barbarian tribes, naval squadrons controlled some 1,250 miles of natural defensive water barriers, including the Rhine, the Danube, and the Black Sea.
One of Julius Caesar's unfulfilled visions had been to join the Rhine and Danube rivers by a canal and thus create a navigable, arterial water route through continental Europe's heart, a Nile of Europe. In the event, the Rhine-Danube boundary remained the defensive frontier between Roman civilization and the barbarian world-an equivalent of China's Great Wall-and never became the central transport waterway unifying northern and central Europe. In the Middle Ages, the old Rhine-Danube frontier again shaped history as the rough, axial dividing line between Catholic and Protestant Europe. Ultimately, it took 2,000 years, until 1992, for political conditions to be conducive for the completion of the 106-mile-long Rhine-Main-Danube canal linking the North Sea and the Black Sea and helping to integrate Europe into a single economic community.
Augustus famously boasted of his legacy that he had found Rome a city of brick and left it a city of marble. Indeed, under the order established by the Roman Empire, wealth and commerce soared. Goods were sucked in by inexorable political and economic gravity from the empire's provinces along its rivers and bordering seas-North, Baltic, Black, Red, and Atlantic-toward its ravenous mouth and stomach in the central Mediterranean. In an era where it was difficult to move any large quantities by land, river and sea transport were Rome's vital lifelines.
At the empire's height, staples and luxuries poured into its bustling ports from distant foreign civilizations spanning the Old World. Grain that became the daily bread dole for commoners came from Egypt, North Africa, and the Black Sea; the rich and powerful enjoyed wools from Miletus, Egyptian linens, silks from China, Greek honey, peppers, pearls, and gems from India, Syrian glass, marble from Asia Minor, and aromatics from the Horn of Africa and the Arabian Peninsula. The mutual attractive force of trade between Rome and its counterpart empire in the Far East, Han China, increasingly found shipping routes through the narrow Strait of Malacca between the Malaya Peninsula and Sumatra to stimulate a vibrant exchange across the long-distance Indian Ocean highway to give critical mass to the nascent global market economy that took hold in this era. Over a hundred trading ships per year sailed the monsoons for India through the Red Sea, parts of which were patrolled for pirates by the Roman navy. Throughout the Mediterranean, the infrastructures of shipping and trade were improved and expanded. In order for large cargo ships to arrive directly at Rome instead of being transshipped in smaller boats from the natural, deep port near Naples, for example, Emperor Claudius in AD 42 constructed a man-made harbor from the dredged marshes north of Rome that was linked to the Tiber by an artificial canal and towpath; inside the harbor, called simply Portus, was a large lighthouse modeled on Alexandria's Pharos lighthouse.
Rome earned its economic surplus both from being the center of sea trade and from imperial exploitation of the rich provinces around the Mediterranean rim whose own political economies were increasingly molded to the necessities and pulse beat of the giant Roman metropolis. With some 1 million inhabitants at its height, Rome was far and away the largest city in Western history and would remain so for nearly 2,000 years. Such a size was far more than it could support on local Italian agriculture and industry. Therefore, as Rome grew rich upon the provincial resources on its periphery, it also grew increasingly dependent upon them for its internal stability. During Rome's zenith, chronically high urban unemployment resulted in a welfare state with up to one-fifth of the often restive population receiving subsidized bread from public storehouses and entertainment at public spectacles-gladiatorial contests, ship races and various games, in venues like the Colosseum and the Circus Maximus. Rome's basic food security required the reliable importation of about 300,000 tons of grain per year. Two-thirds came from destinations within several days' sailing. But one-third came from the Nile Valley in Egypt, which was a difficult and dangerous thirty- to sixty-day voyage into the prevailing westerlies. Emperors from Augustus onward thus placed high state priority on protecting the fleet of huge grain ships that crossed the open waters from Alexandria to Rome. Each cargo carrier was up to 180 feet long and 44 feet deep-larger than any ship that crossed the Atlantic until the early nineteenth century. One famous grain cargo ship passenger who voyaged to Rome in AD 62 was the prisoner St. Paul. The Nile became so important as a breadbasket that Egypt was forbidden by edicts to export its grain anywhere else. Egypt's irrigation was intensified and its cultivated acreage expanded under the Romans, facilitated by a long period of good Nile floods, and even rainfall.
Rome vigorously exploited another of history's seminal water technologies to help it produce the daily bread for so many hungry soldiers and citizens-waterpower. To grind grain into flour to make bread, Rome built vast numbers of waterwheel-powered gristmills on streams and artificial conduits fed by aqueducts that transmitted the energy captured from the flowing current to turn the wheel and the millstone attached to it. As early as the first century BC, Roman engineers had made the ingenious breakthrough of moving the traditional horizontal waterwheel to a position vertical to the water, and to multiply the power it generated through the use of gearing. Many of the water mills built by Rome to feed army garrisons and cities were impressively large and powerful. The famous fourth century AD Roman water mills at Barbegal near Arles, France, used water forced along a six-mile-long aqueduct to drive eight pairs of wheels. It could grind 10 tons of grain daily. It was in imperial Rome that water-powered mills were transformed from small, household and local community devices into tools of large-scale, centralized bread production. As such, they became key instruments of state power.
Why the Romans never fully exploited the enormous work potential of their own advanced waterwheel techniques beyond grinding bread flour is one of the vexing questions of its history. They possessed sufficient know-how to apply waterwheels to industrial uses, such as driving mechanical saws, fullers' beaters, tilt hammers, or bellows to heat iron furnaces. But what they may have lacked, given their surplus of expendable slave labor, was the economic incentive to invest in labor-saving mechanization.
One new water engineering technology that Romans did profitably employ was hydraulicking for mining. Hydraulicking used powerful jets of water that were far more productive than manual digging in the hills of Spain to extract the gold used for its coinage and financial system. Roman engineers released water from large tanks erected 400 to 800 feet over the mining site to generate waterpower sufficient to shear away hillsides and break up rock formations that exposed the valuable gold veins. In the mid-nineteenth century, hydraulicking would have its most famous, intensive modern application at the height of the California gold rush.
Although not famed for their technological originality, Romans did use water to make one transformational innovation-concrete-around 200 BC that helped galvanize their rise as a great power. Light, strong, and waterproof, concrete was derived from a process that exploited water's catalytic properties at several stages by adding it to highly heated limestone. When skillfully produced, the end process yielded a putty adhesive strong enough to bind sand, stone chips, brick dust, and volcanic ash. Before hardening, inexpensive concrete could be poured into molds to produce Rome's hallmark giant construction projects. One peerless application was the extensive network of aqueducts that enabled Rome to access, convey, and manage prodigious supplies of wholesome freshwater for drinking, bathing, cleaning, and sanitation on a scale exceeding anything realized before in history and without which its giant metropolis would not have been possible. That it amply served the poor as well as the rich was likewise a notable development in the history of civic society. Throughout its empire, Rome's aqueducts supported the robust health of towns and frontier garrisons whose soldiers' fitness for battle was a critical element of its army's superiority. Its mobilization of public water that served all classes established a landmark civic standard embraced later by industrial democratic Western societies.
Freshwater conduits had been in use for centuries before censor Appius Claudius built Rome's first aqueduct, the 10-mile-long subterranean Aqua Appia, beneath its first major paved roadway, the Appian Way, in 312 BC. Some four hundred years earlier the Assyrians had built their aqueducts augmenting Nineveh's water supply and Hezekiah had excavated Jerusalem's secret water tunnel. In 530 BC the Greek island of Samos likewise cut a water tunnel two-thirds of a mile long, while classical Athens had several aqueducts. The technical high point of Hellenist water engineering was the Ionian city of Pergamum's early second century BC 25-mile-long aqueduct with double and triple terra-cotta piping and a pressurized section that enabled water to cross a low valley and then rise again on the other side against the natural force of gravity.
What distinguished Rome's public water supply infrastructure was not its originality, but rather its precision, organizational complexity, and grand scale. Spectacular ruins of the famous three-tiered, 160-foot-high arches of southern France's Pont du Gard, the still partly functioning, narrow-arched aqueduct bridge at Segovia, Spain, and the celebrated Roman baths at Bath in England offer glimpses of Rome's widespread hydraulic accomplishments. Roman water systems underpinned the empire in southwestern Europe, Germany, North Africa, and Asia Minor, including at Constantinople, the "New Rome" established by Emperor Constantine at Byzantium on the Bosporus in AD 330.
Yet nowhere was Rome's public water system more influential than in Rome itself. Indeed, Rome's rapid growth to a grand, astonishingly clean imperial metropolis corresponded closely with its building its 11 aqueducts over five centuries to AD 226, extending 306 miles in total length and delivering a continuous, abundant flow of fresh countryside water from as far away as 57 miles. The aqueducts funneled their mostly spring-fed water through purifying settling and distribution tanks to sustain an urban water network that included 1,352 fountains and basins for drinking, cooking and cleaning, 11 huge imperial baths, 856 free or inexpensive public baths plus numerous, variously priced private ones, and ultimately to underground sewers that constantly flushed the wastewater into the Tiber.
As in all ages from antiquity to the present, the pattern of water distribution read like a map of the society's underlying power and class structures. Nearly one-fifth of total aqueduct water during the empire's heyday went to meet the watering needs of patricians' suburban villas and farms. Inside the city walls, paying private consumers and industries and those granted water rights by the emperor were water-Haves who received another two-fifths of Rome's freshwater. Public basins and fountains used freely by ordinary people, by contrast, received only 10 percent of total aqueduct water. Nevertheless, like the bread dole, provision of a minimum amount of free water was an essential pillar of the state's political legitimacy that Roman officials were careful to maintain. The remainder of aqueduct water was allocated to the emperor's ever-growing demands for public monuments, baths, nautical spectacles, and sundry other public purposes. Rome's patrician families enjoyed hot and cold indoor running water, sanitary bathrooms, and water closets that were unsurpassed in comfort until modern times. Unlike today's highly pressurized, enclosed pipe systems, Rome's aqueducts flowed from their source by natural gravity through precisely sloping gradients maintained over long distances; only in the city was pressurized plumbing employed to raise water to elevated locations. Most of the aqueducts were subterranean. But about 15 percent of the system was above ground and ran along its famous arched structures to maintain its gradient over uneven terrain.
Sustaining and housing a population of 1 million may not seem like much of an accomplishment from the vantage point of the twenty-first century with its megacities. Yet for most of human history cities were unsanitary human death traps of inadequate sewerage and fetid water that bred germs and disease-carrying insects. Athens at its peak was only about one-fifth the size of Rome, and heaped with filth and refuse at its perimeter. In 1800, only six cities in the world had more than half a million people-London, Paris, Beijing, Tokyo, Istanbul, Canton. Despite Rome's hygienic shortcomings-incomplete urban waste disposal, overcrowded and unsanitary tenements, malaria-infested, surrounding lowlands-the city's provision of copious amounts of fresh, clean public water washed away so much filth and disease as to constitute an urban sanitary breakthrough unsurpassed until the nineteenth century's great sanitary awakening in the industrialized West.
Although there are no precise figures in ancient records on how much freshwater was delivered daily, it is widely believed that Roman water availability was stunning by ancient standards and even compared favorably with leading urban centers until modern times-perhaps as much as an average of 150 to 200 gallons per day for each Roman. Moreover, the high quality of the water-the Roman countryside offered some of the best water quality in all Europe, and still does so today-was an easily overlooked historical factor in explaining Rome's rise and endurance.
Yet it was a universal testimony to water's perennial economic and human value that even in conditions of relative plenty man constantly desired to have more of it. In an amusing reminder of unchanging human nature, Senator Julius Frontinus, who became Rome's Water Commissioner in AD 97, in his famous short treatise On the Water Supply of the City of Rome On the Water Supply of the City of Rome urged harsh punishment for the many water thieves who "have laid hands upon the conduits themselves by penetrating the side walls." urged harsh punishment for the many water thieves who "have laid hands upon the conduits themselves by penetrating the side walls."
Frontinus modeled himself, almost reverentially, upon the single most illustrious creator of Rome's public waterworks-Augustus's loyal military commander, schoolmate, and virtual coemperor for much of his reign, Marcus Agrippa. In AD 33 Agrippa, acceding to Augustus's request, assumed the office of aedile and with it responsibility for Rome's municipal works and services. Actium was two years in the future and Augustus-still known as Octavian-faced waning public support at home with the outcome of the civil war with Mark Antony very much in doubt. A famously self-effacing, plebeian-born protege of Julius Caesar, Agrippa enjoyed wide popularity with commoners that Augustus lacked. His year-long aedileship would become the most lauded and influential in Roman history. At its start, Rome's public infrastructure, following years of civil discord and war, lay in a crumbling, neglected state. It ended with revolutionary improvements-on a scale often associated with historic dynastic restorations and renewals of civilization-that not only resurrected Rome's municipal infrastructure and services but also Augustus's popularity and much of the political support he needed to overcome Antony, then far removed in Egypt with Cleopatra.
Waterworks were the centerpiece of Agrippa's urban renewal program. In only one year, largely at his own personal expense, he repaired three old aqueducts, built a new one, and greatly expanded the capacity and distribution reach of the entire system. Some 700 cisterns, 500 fountains, and 130 ornately decorated distribution tanks were also constructed, and 170 free public baths were opened for both men and women. He cleaned out the sewers, famously rowing through the Etruscan-built Cloaca Maxima on an inspection tour. In addition, he put on splendid games, distributed a dole of oil and salt, and on festive occasions offered free barbers.
Rome's municipal water system became Agrippa's lifelong passion. In the years after his aedileship, even as he ruled over the eastern half of Augustus's growing empire, led important military campaigns and was considered a leading successor to the emperor when Augustus fell gravely ill, he acted as the city's unofficial, permanent water commissioner and spent lavishly from his own funds for the purpose. In 19 BC he built a sixth new voluminous aqueduct, the Virgo, whose water was acclaimed for its purity and coldness, which he used partly to supply Rome's first large public bath near today's Pantheon.
The Virgo aqueduct, much of which lay underground, had the historical distinction of being the only line never to completely stop flowing through Rome's subsequent dark centuries; today, Virgo water flows in Bernini's famous Quattro Fiumi (Four Rivers) fountain in Piazza Navona and terminates at the Trevi Fountain, where the relief in the left panel shows Agrippa himself supervising the construction of the Virgo with the design plans unscrolled before him. Upon his death in 12 BC, at age fifty-one, he bequeathed his slaves to Rome's water system maintenance crew. His master water system plan was adopted as the basis of the official imperial water administration created a year after his death by Augustus. It guided Rome's water management thereafter, including the major new aqueducts built until the early second century. Longer term, Agrippa's civil works set a standard and concept of public municipal service for all classes, a democratic legitimacy, and tool of exercising political power that is influential in modern liberal Western democracies.
Agrippa's innovation of the first large public bath-soon magnified in scale, vanity, and variety of activities by the 11 monumental imperial baths erected by succeeding emperors-became the model central institution of social and cultural life in ancient Rome. The traditional Republican era bath was transformed from a simple "sheltered place where the sweaty farmer made himself clean" into a multifaceted, sometimes luxurious "community center and a daily ritual that defined what it meant to be Roman," writes historian Lewis Mumford. "The Roman bath compares with the modern American shopping center." A typical Roman's day at the baths started after a day's work and lasted several hours. A large facility consisted of a cluster of activity rooms and big bathing chambers surrounding an open, central garden. The richest baths were adorned with statues, floor mosaics, and marble or stucco reliefs on the walls. Bathers generally would first get an oil rubdown in the unctuarium unctuarium before exercising in one of the gymnasiums. Bathing started in the hot before exercising in one of the gymnasiums. Bathing started in the hot caldarium caldarium and steam room or and steam room or sudatorium, sudatorium, much like a modern Turkish bath, heated by furnaces from below; Romans didn't use soap, but instead scraped the dirt off their perspiring skin with a curved metal instrument, the much like a modern Turkish bath, heated by furnaces from below; Romans didn't use soap, but instead scraped the dirt off their perspiring skin with a curved metal instrument, the strigil strigil. Next, they lounged at length with friends in the tepidarium tepidarium or warm baths, often conversing and carousing together. Then they dipped in the cold bath, or or warm baths, often conversing and carousing together. Then they dipped in the cold bath, or frigidarium, frigidarium, and swam in the pool. Lastly came a rubdown with oils and perfumes. Along the way they ate snacks and sipped wine served to them by attendants, read books from the bath's library, got massages, relieved themselves in multiseated latrines along the walls of the baths, and sometimes indulged in drunken carousing and lovemaking. A full range of bathhouses, from free to costly, were available for all classes. At some, men and women bathed naked together, a practice whose repeated banning by emperors testified to its persistence. From one outpost of the empire to the other, Romans reinforced their Roman identity by practicing the daily social and hygienic rituals of the bath. and swam in the pool. Lastly came a rubdown with oils and perfumes. Along the way they ate snacks and sipped wine served to them by attendants, read books from the bath's library, got massages, relieved themselves in multiseated latrines along the walls of the baths, and sometimes indulged in drunken carousing and lovemaking. A full range of bathhouses, from free to costly, were available for all classes. At some, men and women bathed naked together, a practice whose repeated banning by emperors testified to its persistence. From one outpost of the empire to the other, Romans reinforced their Roman identity by practicing the daily social and hygienic rituals of the bath.
Just as the high and low floods of the Nile tracked the prosperous and low periods of civilization in Egypt, Rome's great eras of achievement and population growth corresponded to its periods of aqueduct building and expanding water supply. The early aqueducts were built during Rome's Italian peninsular expansion as rising population levels overtaxed the city's resources of local freshwater springs and wells and potable Tiber River water. The transformative victory in the Second Punic War in AD 201 was followed by an intensive burst of Republican era aqueduct building featuring Rome's third aqueduct, the voluminous, 57-mile-long Aqua Marcia in 144 BC, which for the first time distributed ample good water across the social spectrum. Agrippa's aqueduct constructions sufficed until the mid-first century AD, when Emperor Claudius increased the water supply by about 60 percent with two new aqueducts, and Trajan added a third in AD 103 to keep pace with the doubling of Rome's population in the early imperial period. The end of aqueduct construction in the early third century, by contrast, reflected the plague-ridden fall in the city's population and the early decline of the Western Roman Empire; indeed, the last aqueduct was built in AD 226 mainly to serve the decadent luxury of refurbishing the emperor's baths rather than the needs of the citizenry.
Other water-related depredations also marked Rome's decline. Rome's heavily fortified European frontier river barriers were breeched by Germanic barbarians: In AD 251 the Goths crossed the Danube; in AD 256 the Franks broke through the Rhine. Both pillaged deep into the empire. In the same period Rome began to lose control of the seas and the security of its food and raw material lifelines to its provinces came under steady assault by pirates, Goths, and other barbarian tribes. Rome's underfinanced and diminished navy increasingly retreated. Hyperinflation, heavy taxation, recession, and severe pestilential disease debilitated the empire's economy from within. Without, new defensive walls were erected around the capital by Emperor Aurelian in AD 271.
Although the empire earned a temporary, century-long reprieve through the administrative reforms, reassertion of military power, and authoritarian economic command of several resourceful soldier-emperors, notably among them Diocletian and Constantine, its command of the sea-lanes and defenses that underpinned its control of vital supplies from its provinces was irreparably breaking down. This was importantly illustrated in its Egyptian breadbasket. In response to onerous taxation payable in grain-tax "rates" were calculated by Roman governors according to the Nile's annual flood level-cultivated cropland in Egypt by the third century had shrunk by half as its farmers grew weary of working for overlords and abandoned their fields. Draconian new grain taxes imposed in AD 313 worsened the long-term situation. Finally, in AD 330 Emperor Constantine transferred the capital itself to a new, more defensible and economically strategic location at the ancient Greek city of Byzantium overlooking the Bosporus Strait gateway to the Black Sea. The regular Rome-bound Egyptian grain shuttles were redirected to the "New Rome," renamed Constantinople. Rome's remaining population was left to fend for itself. As often in history, the change in main water transport routes signaled the shift in destinies among leading powers and civilizations.
The Western Roman Empire's final demise accelerated in the late fourth century AD. The proximate cause was a new wave of incursions by Gothic and other barbarian tribes put to flight by the invasion into eastern Europe from the central Asian steppes of a fearsome, nomadic tribe, the Huns. The Huns, who eventually settled in the Danube valley, themselves had been propelled into motion by their own ejection from their Asian homelands by an even more warlike group, the Mongolian Juan-juan war confederacy, which also constantly menaced China. By AD 410, when traitors opened Rome's gates to Alaric, the Visigoth leader, for the traditional three days of sacking, the imperial Western seat of its government already had fled to safety at Ravenna, where the mucky coastal marshlands afforded better natural defenses from cavalry and barbarian armies.
Rome's aqueducts also figured prominently in the city's subsequent history and its ultimate renaissance as a center of world civilization. In the mid-sixth century, Byzantine Roman emperor Justinian made a major effort at revival when he tried to retake Italy from the Goths. The Eastern Empire had prospered from its seat at Constantinople and even had launched a formidable new navy. Justinian assigned the exceptionally talented general Belisarius to undertake the recovery of Italy. In 536 and 537, Belisarius successfully conquered northward from Sicily, took Naples by sending 400 soldiers undetected through an aqueduct he had drained during the siege, and then entered Rome without a fight when the Goths evacuated it as indefensible. Destroying Rome's aqueducts was one of the first targets of the Goths in their countersiege against Belisarius. Water ceased to flow almost everywhere; baths, drinking fountains, basins, and sewers went dry. Citizens were forced to crowd into the low-lying areas closer to the Tiber and rely upon the river and wells for their freshwater. The cutoff of the aqueduct flow also shut down the big waterwheel-powered gristmills on the Janiculum, the steep hill near the modern Vatican where much of the city's daily bread was produced. The ever-resourceful Belisarius responded by constructing floating water mills, moored between two rows of boats, under the Tiber bridges where the currents are artificially accelerated-such floating water mills later became commonplace under medieval European city bridges. The Goths tried to jam or break the waterwheels by throwing the bodies of slain Roman soldiers and tree trunks into the Tiber, but Belisarius thwarted them by laying a protective chain across the river to catch the debris.
The Goths also secretly probed the empty aqueduct channels in the hopes of gaining surprise entry into the city. They might have succeeded had not a Roman sentry at the Pincio Hill gate glimpsed the flickering torch light of Goth soldiers as they passed a shaft rising to the surface from the subterranean channel of the Aqua Virgo. The sentry concluded he had seen the gleaming eyes of an errant wolf. Belisarius, however, insisted on an investigation that exposed the Goths' incursion. He ordered the sealing up of all the aqueduct channels. After defending Rome, Belisarius moved north. In AD 540 he took back Ravenna, which the Goths had made their capital. His success and growing popularity, however, made Justinian uneasy about his ambitions. He was recalled. In the end, Justinian's dreams of imperial restoration scarcely outlived him. A new wave of barbarian invasions, this time led by the Germanic Lombards, soon overwhelmed Italy.
By the end of the sixth century, with most of its aqueducts and sewers in ruins and its buildings crumbling, as Rome biographer Christopher Hibbert describes it, "Rome's decay was pitiable...the Tiber carried along in its swollen yellow waters dead cattle and snakes; people were dying of starvation in hundreds and the whole population went about in dread of infection...The surrounding fields, undrained, had degenerated into swamps" infested with malaria-bearing mosquitoes. The city's population had shrunk to only 30,000. An anti-Lombard alliance between the Papal States and the Frankish Carolingians-reaching its apogee in AD 800 with the St. Peter's Christmas Day coronation of Charlemagne as Holy Roman Emperor-and a papal effort to marshal peasant labor to repair some of the aqueducts failed to endure. By 846 Muslim pirate vessels traveled up the Tiber and plundered St. Peter's.
The Mediterranean West's free-market seafaring and republican democratic traditions, however, were not totally extinguished on the Italian peninsula. Instead, they were transplanted after AD 400 to a cluster of islands in a very shallow 200-square-mile saltwater lagoon intersected by a few deep channels at the head of the Adriatic Sea to which prosperous Roman citizens from the countryside had fled for safety from the barbarian marauders. Venice was destined to become the most precocious of the early Italian city-states, the preeminent sea trading and naval power in the Mediterranean, a progenitor of the modern market economy and the longest lived democratic republic in world history. By AD 466 the dozen tiny island communities began to elect representative tribunes to coordinate affairs among themselves. The first doge, or duke, was elected ruler in AD 697 in what would be an unbroken line of democratically chosen successors until the Venetian republic was finally overrun 1,100 years later in 1797 by French conqueror Napoleon Bonaparte.
Venice lent its nascent naval power in the Adriatic to assist Belisarius and the Byzantine Empire, in what would become a long, complex, competitive alliance between the two greatest sea powers of Christian civilization in a Mediterranean soon threatened by the ascendant commercial and military forces of Islam. It was through Venice that the historic bridge of continuity was established between the early republican seafaring trading traditions born in the ancient Mediterranean and the sea-oriented, liberal market democracies that later rose to world preeminence in post-Renaissance western Europe.
The revival of the city of Rome itself began in 1417 with the end of the Great Schism and the return of the reunified papacy to Rome in the person of Martin V. For want of drinking water, much of Rome's population at the time was still clustered in ramshackle houses close to the filthy Tiber. One of Martin's earliest acts upon returning to Rome was to repair the still partly functioning Virgo Aqueduct that had eluded total destruction by the Goths. Over the next two centuries, several of Martin's successors, notably including Nicholas V, Gregory XIII, Sixtus V, and Paul V-known collectively to historians as the "Water Popes"-dedicated themselves to rebuilding Rome's water system and adorning it with the high Renaissance fountains still admired today. As the water returned, so did Rome's population and the city's grandeur. Rome's population doubled to 80,000 by 1563, reached 150,000 in 1709, and rose to 200,000 by the time of the birth of the Italian state around 1870. Fittingly, the last pope before Rome's integration into democratic Italy completed the redesign of the Republican-era Marcia aqueduct, which became Rome's first to operate under modern-era pressure with pumps.
CHAPTER FIVE.
The Grand Canal and the Flourishing of Chinese Civilization Although intensive irrigation society developed latest in China among the river-born, cradle civilizations of antiquity, its water management achievements surpassed all the others. China's inventive, adaptable, and wide-ranging water engineering responses to its diverse environments was the foundation of what became the most precocious, preindustrial civilization in world history. "The Chinese people have been outstanding among the nations of the world in their control and use of water," observed Joseph Needham in his classic Science and Civilisation in China Science and Civilisation in China.
China's ancient civilization arose in a landscape markedly different from other hydraulic societies. It began in the semiarid inland north where the Yellow River in its middle reaches exited the barren steppe highlands of Mongolia and carved a large bend through plateaus covered with deep deposits of soft, flakey, yellowish rich soil, called loess, left by the receding ice age. The climate on these stark plateaus, larger than the size of California, was harsh: frigid in winter, scorching hot in summer, prone to droughts, dusty whirlwinds, and occasional summer downpours that eroded the soft cliffs and washed its loess soil into the Yellow, choking it with the thick silt that gave the river its name and enriching the north China floodplain into which it spilled. Yet the plateau's combination of ample river water, easily farmed and drained soils, and military defensibility provided fertile conditions for a single season of intensive, field grain agriculture. The best adapted crop was millet, a tough grain capable of surviving prolonged dry periods. Gradually, farming was extended throughout the large, loess-enriched, northern floodplains. Most extraordinarily, however, China's civilization achieved the rare accomplishment of hurdling its geographic origins over time to transplant itself far beyond its mother river region to a radically different habitat south of the 33rd parallel dominated by the voluminous Yangtze River. In contrast to the semiarid north, the Yangtze region was rainy, humid, verdant, mostly hilly, heavily monsoonal, and civilized by the intensive cultivation of an entirely different crop, wet rice.
The outstanding, transformational event that catapulted Chinese civilization above all its contemporaries, and marked one of water history's turning points, was the completion in the early seventh century AD of the Grand Canal-still mankind's longest artificial waterway, extending over a distance equal to that between New York and Florida. The south-north-running canal linked China's two disparate, giant river systems and habitats to create the world's largest inland waterway transportation network. Just as the Nile had unified Upper and Lower Egypt, China became integrated into a militarily defensible nation-state with a strong, centralized government that commanded an expansive diversity of highly productive economic resources. The Grand Canal played a catalytic role not only in China's becoming the world's most precocious civilization during the Middle Ages but also in the country's fateful fifteenth-century decision to turn its back on the rest of the world that ultimately led to its prolonged, slow decline.
The Grand Canal was so successful because it bridged China's underlying hydrological fault line: north China's chronic insufficiency of accessible freshwater resources to fully irrigate its superabundance of rich soil to achieve its maximum food-growing potential, and south China's opposite profile of having more water than could be productively employed on its less fertile soils. Managing this north-south water and land resource mismatch has been a recurring, central technical and political challenge of Chinese governance in every era since imperial times.
Both the 3,400-mile-long Yellow and the 3,915-mile-long Yangtze originated in the Tibetan plateau in the Himalayas. Beyond that their signature flows and environmental characteristics diverged sharply. The Yellow was shallow and by far the world's siltiest river-30 times siltier than the Nile and nearly three times more than the famously muddy Colorado River. A dipperful of its water was commonly said to contain 70 percent mud. It was the rapid buildup of eroded silt from the loess plateaus that caused the Yellow to frequently overflow its banks in unpredictable, devastating floods across its lower plains. So many millions perished and lost their livelihoods in these fearsome floods over the centuries that the river became known as "China's Sorrow." Its greatest floods-some carving new paths as far as 500 miles away to the Yellow Sea-repeatedly fomented political and economic upheavals throughout Chinese history. Building tens of thousands of miles of levees to try to contain the Yellow within its banks, and rebuilding them after the inevitable failures, was thus always a top political priority of every Chinese dynasty.
The huge Yangtze, by contrast, carried some 15 times more water than the Yellow, with deep navigable channels and many large tributaries that made it an ideal transport highway for large vessels once its waters had descended the mountains and wound its way through its deep canyons and gorges to enter its enormous lower basin and swampy delta. The Yangtze's seasonal monsoon floods regularly inundated the region; every half century or so, however, the combined rush of descending water and the engorged flow from its tributaries created giant waves that overwhelmed all man-made flood control infrastructure and resulted in devastating floods. When China's climate was moister in ancient times, the central section of the Yangtze had been a gigantic swamp, far too wet to sustain large-scale civilized human settlement. Gradual desiccation, and Chinese advances in water redirection, terracing, drainage, and other wet rice irrigation techniques gradually transformed the region into prosperous farmland. By medieval times it was producing the greater part of China's food, with rice surpluses distributed along its extensive tributary network and to the Yellow River region in the north via the Grand Canal and coastal sea routes. Political control of the "golden waterway" of the Yangtze thus joined flood control as a vital linchpin of Chinese power. So closely correlated was river management and governing power that the very Chinese character for "politics" is derived from root words meaning flood control.
China The Silk Roads [image]
The traditional founding father of China's Yellow River civilization was Yu the Great. A water engineer, Yu rose to power on the merits of his accomplishment as the tamer of the great floods that ravaged settled life in the Yellow basin before recorded history. By having "mastered the waters and caused them to flow in great channels," he made the world habitable for human society. In honor, the tribal confederation elevated him to leadership. He went on to found the Bronze Age Xia dynasty from about 2200 to 1750 BC, and he became venerated as the lord of the harvest in association with the river's early irrigation works.
Yu's legend reflected the paramount importance of water control in Chinese history. At birth it was said he emerged, fully formed, straight from the dead body of his father, who had previously tried and failed to control the floods by damming and diking the river's flow, and had been put to death for stealing magic soil from heaven in order to build a dam. After careful study and surveys, Yu took up his father's task by the different approach of laboriously dredging river channels and digging ditches and canals, including one bored through a mountain, in order to divert excess floodwaters to the sea. He labored selflessly alongside the workers, and after many years, finally succeeded in bringing the Yellow River and its floodplain under control. Confucius hailed him as the ideal of the humble, qualified government official who used his power for the public good, and thus the aspiring role model for China's technocratic elite who governed in support of its emperor.
Water management helped frame the historic Chinese philosophical debate about the right principles for man's governance of himself and his relations to the natural order. The sixth century BC Taoists argued that humble water's yielding, yet relentless flow that wore down all hard and strong obstacles expressed the essence of nature and provided an exemplary model for human conduct. Taoist engineers designed waterworks to allow water to flow away as easily as possible, exploiting the dynamics of the natural ecosystem, just as they urged Chinese leaders to gradually win support for their goals through persuasive dialogue. Their main rivals, the Confucians, on the other hand, advocated a more forceful manipulation of both nature and human society to achieve the public good. They believed that rivers had to be forced, through dikes, dams and other obstructive constructions, to do man's bidding as defined by rulers and technocrats. Although the Confucian view prevailed as the guiding tendency of Chinese hydrology from the Han Empire in the late third century BC to the twenty-first century postcommunist state, the underlying principles framed a fundamental engineering debate which has reemerged on the global level today as the world seeks environmentally sustainable solutions to the water scarcity crisis.
After nearly half a millennium, Yu's Xia dynasty was displaced as the predominant power by the Shang and later the Zhou dynasties. Each was centered along a different, but overlapping part of the inland Yellow basin and flourished on indigenous irrigation agriculture without significant river or seaborne trade with other regions. The Shang was a Bronze Age tribe that with the help of the chariot imposed an aristocratic rule from about 1750 to 1040 BC over an area centered in the fertile north China plain and within reach of the Yellow River region's tin and copper deposits. Although they were one of the earliest literate cultures east of Mesopotamia, the Shang's many primitive customs included ancestor worship, human sacrifice, and various ritual consultations with the spirits by priestly diviners. The excavations at their city of Anyang yielded tens of thousands of "oracle bones" that were consulted by priests to reveal answers to the vital questions of life and death such as whether it would rain or when the barbarians from the north would attack.
North China's climate was still much warmer and moister than today, and large-scale irrigation depended on extensive reclamation of cropland by draining fens and marshes by mass organized manpower. Their highly stratified social organization and large public works, including extensive walled cities, fit the model of the hydraulic civilization. Startling confirmation that millet was one of their staple crops was made in 2005 when archaeologists exploring the remains of an ancient village buried by an earthquake and flood discovered a bowl containing a well-preserved 4,000-year-old millet noodle 20 inches long.
With the conquest and amalgamation of the Shang culture by its former vassals, the Zhou dynasty, centered on its western border along a tributary of the middle Yellow River, more of the distinctive character of the emerging Chinese state took shape. While retaining the older dynasty's use of kinship as the basis of political organization, the Zhou introduced the enduring political concept that the emperor's ruling legitimacy stemmed not solely from divine right of birth but from a "Mandate from Heaven" based upon moral performance. Water control was a key test of the mandate. A good emperor was expected through magic and ritual to be able to deliver vital things like rain, peace and good harvests; droughts and floods, on the other hand, were events that signaled heaven's disapproval. One legitimizing boon to Zhou crop irrigation was the innovation during their reign in the sixth century BC of productivity-enhancing iron tools. The advent of iron, however, also stimulated the deployment of new weaponry. From about 400 BC, what would emerge as the unified Chinese state was forged over nearly two centuries of incessant warfare between seven competing regional powers. During this period, the flight of northern farmers from the war zones accelerated the migration of Chinese civilization to the cultivation of rice paddies in the warm, wet south. Although China's rice farming would not achieve its full critical mass until the seventh century AD, by the time the Ch'in dynasty consolidated its victory over its rivals in 221 BC-giving China its modern name-its domains extended throughout the Yangtze basin to the eastern seaboard.
For a dynasty whose own rule lasted only fifteen years, the Chin's legacy was remarkable. Their new political structure of all-powerful emperor with a centralized bureaucracy replaced the old feudal system. Uprooted aristocrats were compelled to move to the emperor's capital, while their local estates were superseded by a system of provinces and counties ruled by governors loyal to the emperor. Standardization was applied to weights and measures, writing systems and currencies, census-taking was begun, and taxation ruthlessly levied.
Like many great founding or restoring dynasties, the Ch'in were prodigious builders. Their accomplishments included building a vast road network and early segments of the Great Wall against marauding northern nomads. Of critical importance to their rise and legacy was the construction of large-scale, sophisticated irrigation and transport waterworks. Three in particular stood out. In their home state near the middle Yellow River they completed the Cheng-kuo Canal in 246 BC. By diverting water from two tributaries of the Yellow, it irrigated vast acreage in the Wei river valley north of its capital of Xi'an, site of the famous life-sized terra-cotta army of 8,000 soldiers, horses, and chariots that guarded the original Ch'in emperor's tomb. Although heavy silting limited the irrigation canal's productive life to a century and a half, the great increase in food and population it yielded played a vital role in providing the wealth, weaponry, and manpower the Ch'in needed to complete their conquest of China during the Warring States period.
Even grander and more impressive were the irrigation works of western Sichuan, north of the upper Yangtze, undertaken by a water engineer so accomplished he seems almost to have been an avatar of Yu the Great. Li Bing had been appointed provincial governor in 272 BC, nearly half a century after the region's conquest by Ch'in generals. To enrich the province and win loyalty from the local population, he embarked upon an ambitious hydraulic engineering scheme intended to provide at once flood protection and reliable irrigation from the rapidly flowing, unpredictable waters of the Min River to the surrounding farming floodplain. Li Bing's celebrated waterworks-still flowing today-were constructed chiefly along Taoist precepts. Rather than directly block the river's forceful flow with a dam, a series of diversion weirs were built from flexible bamboo cages filled with rocks that were situated at a juncture where the natural contours of the river facilitated its division into an outer and an inner channel. The weirs could be adjusted to direct more of the water to one channel or the other depending upon conditions-to the outer channel to divert water against flooding or to the inner channel when irrigation water was needed. Li Bing emplaced three upright stone figures in the water as signal gauges. When their feet grew visible, the weir's gates were to be opened to water the fields; when their shoulders became covered, the gates were closed. To complete the irrigation diversion so it could reach the farmland in the Chengdu plain below, Li Bing's workers laboriously cut a channel through the mountainside by heating the rock by bonfire, then dousing it with water until it cracked and could be chipped away. Li Bing's waterworks transformed the plains of eastern Sichuan into one of China's most affluent irrigated farming zones. Covering some 2,000 square miles it sustained a population of 5 million-the maximum supported by the Egyptian Nile from ancient times until the nineteenth century. The outer channel also provided navigability. Later, in medieval times, Li Bing's flowing Min River canals in the plains found additional employment turning thousands of waterwheels to hull and grind rice, and to power textile spinning and weaving machinery.
Li Bing also improved Sichuan's production of precious salt by drilling early brine wells, some more than 300 feet deep, that drew salt directly from its underground sources rather than relying upon traditional salt harvesting from briny pools that had seeped up from the earth. His successors learned to use long, bamboo tubes with leather flap valves to create suction to draw the saltiest water from the deepest recesses. Bamboo plumbing became the mainstay not only of salt works, but eventually was applied ubiquitously throughout south China's rice paddies by farmers as conduits for pump-lifted and relocated water and also in cities as rudimentary water mains.
The Ch'in's third extraordinary water project was the Ling Chu, or Magic Canal, the world's first transport contour canal, which was dug by following the natural topography of the surrounding landscape to avert complex tunneling and water-level management problems. By controlling and joining two rivers that flowed near each other in opposite directions, the 20-mile-long Magic Canal created a waterway link through the mountain ranges dividing northern and southern China. Built on the orders of the Ch'in emperor to support the conquering armies he had sent south in 219 BC, the Magic Canal made it possible to travel by boat through natural waterways and earlier channel cuts all the way from the lower Yellow River, south to the Yangtze, and beyond to the port of Canton-an astonishing distance covering 1,250 miles. Nothing like it had ever existed before in history.
The greatest beneficiary of this unprecedented precursor of the Grand Canal was not the Ch'in, however, but their immediate successors, the Han. Under the four centuries of Han rule, from 206 BC to AD 220, China's powerful centralized state and high civilization flourished as one of the two greatest on Earth. Historians frequently have noted the many historical parallels between the Han and Roman empires. Their periods of greatest power, wealth, and influence were contemporaneous, their empires were of comparable geographic size, they flourished at the extreme edges of the civilized world at the time, and the proximate causes of the demise of each were barbarians attacking from the northern frontiers. Of course their political economies, cultures, and hydrological underpinnings were quite dissimilar. Rome did little intensive irrigation, relied for its wealth upon its Mediterranean sea-linked network of colonies, encompassed many cultures, and honored individualism. The Han Empire, by contrast, was the epitome of a hydraulic state: inward-looking and land-oriented, based upon intensively irrigated agriculture, and governed top-down by a despotic emperor and a cadre of expert technocrats overseeing mass peasant laborers.
The Han wasted little time in marshaling forced labor to add and improve canal segments to the great transport waterway they'd inherited, along with so many other remarkable, nation-building achievements, from the Ch'in. Much of their success was also owed to the extensive construction of irrigation and flood control canals, dams, and dikes, including some forty major water projects to control the Yellow River. Under the Han's centralized administration, the patchwork of cropland in the Yellow River valley was organized into a single, intensively irrigated continuum that created China's classic landscape and served as the economic and political heartland of the empire. Treadle chain pumps, a simple but extraordinarily useful small-scale technology for lifting water operated by the simple stepping motion of as few as one or two individuals, invented in the first century AD, was widely applied across China for drainage and irrigation and to supply drinking water. Eventually all water planning was centralized in a national office, establishing a tradition that has endured to the present day.
By 100 BC the Han state had become the largest landowner, with government monopolies also instituted over vital goods like iron, salt, and wine. Private merchants and the nascent profit-driven market system that had begun to develop under the Ch'in but conflicted with Confucian precepts of governance were suppressed by regulation. Sovereign taxing power was used to weaken disfavored classes and accrue authority to the Han state. In time, all urban markets became government controlled, with officially set commodity prices and taxation on commerce that filled the treasury.
The Han's bid for state domination over economic life was made easier by the fact that wealth creation remained predominantly based on intensively irrigated agriculture at inland locations along mostly navigable, relatively easily governed arterial rivers. Despite China's long coastline, sea trade-always problematic for sovereign states to control-remained underdeveloped due to the geographical fact that there were simply few enticing, easily reached Far Eastern civilizations with whom to profitably trade. Although some unregistered itinerant merchants survived and even flourished trading between cities and at the peripheries of society, mainstream Chinese civilization developed a strongly inward-looking orientation that tended to accrue great power to the central state.
The Han emperors encouraged the expansion of industry, some using water as a vital input. Most importantly this included its precocious iron casting industry. A process for casting iron into molds, one of history's key inventions, had been discovered in China as early as the fifth century BC, nearly 1,800 years before cast iron became widespread in Europe. In the third century BC, the Chinese iron masters discovered a heating and cooling process that produced a malleable cast iron with the strength and solidity that rendered it nearly as good as steel. The Han employed it in important applications, such as making cast-iron plowshares for agriculture and pans in which brine could be evaporated for the mass production of salt. Within two years of nationalizing all cast-iron manufacturing in 119 BC, Han leaders had established 48 state foundries that employed thousands of workers. To achieve the high temperatures necessary for casting iron, the Chinese employed efficient bellows to stoke the blast furnaces. An early innovation that greatly increased cast-iron production was the application of waterwheel power to the bellows. In AD 31, noted Chinese engineer Tu Shih invented a powerful, widely imitated, water-driven bellows used to produce cast-iron agricultural implements.
Unlike the Romans, who used waterwheels chiefly to grind grain and for mining, the Chinese also pioneered the large-scale application of waterpower for industrial production. Indeed, for well over a millennium, China was the human civilization's leader in harnessing water as energy to do useful work. Powerful vertical waterwheels, with gearing to turn several shafts, were used to operate trip-hammers to pound iron into shapes, hull rice, and crush metallic ores, as well as for other applications, by the AD 200s and 300s, many centuries before they appeared in Europe. By AD 530 Buddhist monasteries in the northeastern city of Loyang were even operating waterwheel-powered flour-sifting and -shaking machines based on the same essential design as that used by the steam engine-albeit with the crucial absence of steam power itself-that would galvanize England's eighteenth-century Industrial Revolution.
Not surprisingly, the Chinese would become world pioneers in ensuing centuries in applying waterpower to the ancient art of silk making-one of trade history's great monopolies that enriched imperial China for centuries. The art of producing silk filament from the cocoons of the mulberry silkworm and weaving it into textiles was first discovered as far back as the Stone Age. Hot water played a critical role in the silk-making process, in what was perhaps history's earliest example of water use in industrial production. To net one pound of raw silk, silkworms had to eat 100 pounds of mulberry leaves and produce about 15 pounds of cocoons. Great skill was required to unwind the silk filament from the delicate cocoons. It was accomplished by first soaking the cocoons in boiling water to kill the chrysalis; the strands were drawn out, then joined together and finally woven to produce the soft fabrics desired worldwide.
The Romans first encountered silk in 53 BC when fighting the Parthians in modern Iran. By the first century AD, Roman demand for popular Chinese silk became such a burden on Rome's balance of trade that Emperor Tiberius tried to forbid the importation of silk garments. China's monopoly advantage in the silk trade with the Roman world endured for another 500 years. It was finally broken by a famous case of industrial espionage when two Christian Byzantine monks traveling in China stashed silkworm cocoons in the hollow of their staffs and returned with them to Constantinople, which promptly established its own lucrative silk industry by the end of the sixth century.
The Han began shipping large quantities of silk to Persia and the Levant on taxed and protected camel caravans across the famed 4,000-mile-long Silk Roads of arid central Asia in 106 BC shortly after discovering, to their surprise, the existence of a fairly advanced civilization in the far West-Rome. The availability of freshwater sources dictated the trade routes and the scale of the camel trains. The several Silk Roads started at the huge city of Chang'an (the former and later X'ian) in the Yellow River valley, skirted inside the Great Wall to the Jade Gate and then went beyond China's borders to follow a string of oases across the harsh wind- and sand-blown high deserts of central Asia at the foot the Himalayan, Altai, and Tien Shan mountains. Oases formed wherever mountain streams rushed down, sometimes flooded by snowmelt or violent storms. A northern and a southern route came together between the Jaxartes and Oxus rivers and crossed through Samarkand and Bukkara in modern Uzbekistan, before following various roads through Persia and Mesopotamia to Roman Syria on the Mediterranean; another branch route headed south to India.
The entire trek was made possible only by the astonishing strength and water-storing capacity of the two-humped Bactrian camel, which unlike its one-humped Arabian cousin was able to tolerate the freezing temperatures of the high Asian deserts. Caravans of sturdy, woolly Bactrian camels plodded 30 miles per day carrying 400 pounds of goods on their backs. Although larger trains offered greater safety, most of the caravans were no larger than 50 men and their beasts since that was all the scarce water resources en route could support at any one time.
Many of the oasis outposts thrived as important entrepots of civilization, where both high-value luxury goods and new ideas were exchanged free from government control. In addition to silk, China shipped iron goods, ceramics, jade, and lacquer; the West sent back gold, ivory, precious stones, coins, glass, Persian sesame seeds and nuts, and, from India, spices and perfumes. Buddhism entered China and the Far East from India along the Silk Roads, its teachings spread by two Buddhist monks in the first century AD, overlapping the simultaneous early spread of Christianity in the Roman Empire.
Trade on the Silk Roads reached its apex in the seventh and eighth centuries. Then, suddenly, after the annihilation of a Chinese expeditionary force by a Muslim army at the Talas River near Samarkand in 751 helped trigger the collapse of Chinese power across central Asia, the Silk Roads closed for over four centuries. It was one of history's obscure skirmishes that in retrospect had outsized consequences. The silk trade was redirected to the Indian Ocean spice routes that were increasingly dominated by Muslim shipping, accelerating the rapid rise and global reach of Islamic civilization. The Silk Roads were finally reopened for travel by the Mongol Empire, whose thirteenth-century conquests under Genghis Khan and his heirs spanned from China to Persia. It was at the end of the thirteenth century that Venetian Marco Polo, a jewel merchant, made his famous trading expeditions from Venice to the Mongol overlords of Cathay (China). But by that time the Muslim-controlled, two-way seasonal monsoonal Indian Ocean sea route had established itself as the most reliable and economical way to transport goods between East and West and retained the predominant share of the traffic.
With the fall of the Mongols, the glory days of the Silk Roads ended forever. But the combination of these two overland and sea routes succeeded in establishing an enduring, unregulated, long-distance, Old World trading network based on market economic exchange that competed with and would eventually supplant the traditional authoritarian command organization of centralized states. International trade had reached a peak at the contemporaneous high point of the Roman and Han Empires in the early Christian era. It then eroded with their declines. But gradually, with the restoration of civilized order in the Orient and Occident it built up again. By about AD 1000 the web of international exchange had achieved a critical mass of sufficient density and volume to propel its expansion throughout the second millennium and ultimately evolve into the integrated global market economy of the twenty-first century.
The Han empire finally collapsed in AD 220, like Rome, under pressure from barbarian raiders from its northern frontiers and internal depopulation and weakening from exposure to unfamiliar infectious diseases inadvertently imported on trading ships and Silk Road caravans. Indeed, the Han imperial state had never fully recovered from the combination of a short-lived usurpation and a disastrous course change of hundreds of miles in the flooded Yellow River in AD 11. The delay of several decades in repairing the river's damaged irrigation and protective infrastructure led to inadequate food supplies, famine, disorder, and massive emigration along China's vital northern defensive frontier. Manpower shortages, in turn, weakened the size of the Han's military presence. But the essential underlying reason for the Han's eroding northern strength was its inadequate supply and control of irrigation water to grow enough food to maintain a sufficiently large army there-north China's relative shortage of water resources. A third-century Chinese report highlighted that "there was insufficiency of water for the fullest use to be made of the productive power of the soil." Nor was there yet in place any efficient network to transport compensatory southern food supplies to the northern borders.
The historical parallels between Rome and China endured into the sixth century AD with native efforts to reconstitute the fallen empires in each region. The initiative of Constantinople's Byzantine Roman emperor, Justinian, to reunify the Latin West ultimately failed, leaving Rome itself as a shrunken ruin of its former glory until the Renaissance. In China, by contrast, reunification succeeded. Restoration under the Sui from 589 to 617 AD and the successor T'ang dynasty until AD 906 paved the way for China's medieval economic revolution and its golden age when Chinese society soared to the zenith among world civilizations.
Why did China's reunification succeed, yet Rome's fail? One outstanding distinction was China's building of the imperial Grand Canal linking the Yangtze and the Yellow rivers. Completed at a breakneck pace in only six years in 610 by the Sui-who, like the Ch'in, were prodigious and ruthless infrastructure builders-using some 5 million conscripted male and female laborers, the nearly 1,100-mile-long, elongated S-shaped Grand Canal linked up local canal segments that had been built episodically since the fifth century BC and added new segments. In all, it created a stupendous 30,000-mile-long national inland waterway system that enabled a united China to ship vital rice supplies grown on the terraced hillside paddies of south China to the large population centers and army troops located on the Yellow River to defend against the continuing threat from bellicose nomadic horsemen from the Asian steppe.
Not only did the Grand Canal overcome the vulnerability that had vanquished the Han. By bridging China's north-south hydrological fault line, it synergized the natural and human resources of the two diverse geographical zones to help launch China's brilliant, medieval golden age. All China was invigorated with fresh economic and cultural energy. In contrast to the Han, the Sui and T'ang dynasties presided over a more robust double base, one in the traditional Yellow River valley in the north and an even more productive southerly one that had been steadily growing for centuries around the Yangtze.
The old Roman Empire and Europe, by contrast, lacked the unifying impetus of any such inland waterway. Its major arterial river system, the Danube-Rhine, was ill-suited to that purpose because it flowed away from the early hubs of Mediterranean European civilization, through difficult, rain-fed agricultural soils, and along an unstable frontier boundary besieged by warlike tribes. The open waters of the Mediterranean were far less effectively controlled and thus less conducive to playing a uniting role than large irrigation rivers. From this point on, the histories of China and Europe diverged widely. While the European territory of the old Roman Empire remained a fragmented jigsaw of competing states and endured the stagnation of the long dark ages, the Grand Canal served as the electrifying fulcrum of China's medieval economic revolutions in transport, agriculture, and industry.
China's Grand Canal was one of mankind's stellar engineering achievements. It was the largest artificial transport waterway ever built and required a larger labor force than the one that erected the Great Wall, most working with their bare hands and shovels and uncounted hundreds of thousands giving their life to the project. It ultimately spanned eastern China for 1,100 miles from the port city of Hangzhou south of Shanghai to Beijing on the northern frontier with a gigantic channel 10 to 30 feet deep and up to 100 feet wide. It featured 60 bridges and 24 locks to manage elevation variations and summit level water flows. Its waters teemed with commercial vessels of all shapes and sizes, powered by sail, oars, and paddle wheels, transforming the world's most densely populated trading area into a single national economic market. Rice-laden barges came and went from huge granaries that the government maintained at key junctures along its route to furnish the food lifeline for China's national security. The easy movement facilitated centralized governance by grain tax collectors, bureaucrats, and soldiers en route to army garrisons. Due to its surpassing importance, the Grand Canal became a key political barometer, and driver, of Chinese history. Whenever the canal was threatened, cut, or left in a state of disrepair, China was generally in the throes of a crisis or immersed in prolonged decline or political lassitude. A robust Grand Canal system, on the other hand, spurred internal growth and security, rendered superfluous the pirate-harassed sea transport links between the southern food supply and the northern defensive garrisons, and generally encouraged China's inward-looking, autarkic impulses.
As a result of the canal, water transport became many times less costly, at least one-third less than shipping by land. Government policymakers made ongoing improvements a top priority. One key advancement was the world's first double canal pound lock at an opening onto central China's Huai River. It was built in AD 984 at the order of Ch'ia Wei-yo, a Sung government assistant transport commissioner, who was seeking ways to minimize theft and damage to ships and cargo caused by existing methods for moving vessels between differing water levels. At the time, cargo ships were manually hoisted out of the water with ropes by large labor crews, dragged up a slipway ramp cut into the bank, and then relaunched from a second slipway into the water at the level of the second waterway. Pound locks, which came into widespread use on the Grand Canal network during the eleventh century, impounded water between two lock gates; vessels were either lifted or lowered simply by adding or withdrawing water within the impounded portions. Boats could easily be lifted up to five feet in a pound lock. A graduated series of pound locks enabled canals to lift boats to unprecedented elevations-the summit level on the Grand Canal, for instance, was 138 feet above sea level. Moreover, the pound lock conserved precious water, allowing canals that often went dry in summer to operate more days of the year. One double lock built where a branch of the Grand Canal joined the Yangtze enabled the passage of ships five times larger than possible under the double slipway system.
River cargo volumes soared from early T'ang times. In the eighth century, combined tonnage of the government's 2,000 ship Yangtze salt and iron fleet alone reached a third of the total transported on all British commercial vessels in the mid-eighteenth century. During the Sung dynasty from 960 to 1275 government officials improved their communication by using the waterway to distribute the world's first national newspaper, an official government gazette. As shipping traffic increased, private shipping brokers became increasingly active, matching and administering contracts between buyers and sellers, storing goods at their warehouses and serving as clearinghouses of market prices and conditions. Where the commerce of inland waterways merged with the sea, great port cities with market activity arose to trade in spices, silk, and other luxuries with the rest of the world through shipping networks that extended across the Far East, India, Arabia, and the Mediterranean.
During the T'ang era, the Chinese were content to sail the seacoasts with the two-way monsoons, south in winter and north when the winds reversed in summer, and to rely upon Arab, Persian, and other foreign shippers for long-distance sea trading. By the Sung dynasty, Chinese nautical mastery was world class, featuring massive ships built with iron nails from its foundries, watertight compartments unknown in the rest of the world, a huge sternpost rudder for steering, buoyancy chambers, and distinctive, narrow fanlike sections of canvas sails stretched between bamboo masts that looked much like a Venetian blind. Navigation was facilitated by the invention in 1119 of the mariners' compass, one of many important Chinese innovations to migrate westward. As a result, Chinese seafaring gradually grew more ambitious. Yet seafaring in China's golden age never approached the awesome scale of its inland river shipping, which so impressed Marco Polo, native of Europe's greatest seaport, Venice, then with a comparatively tiny 50,000 inhabitants. Describing the Yangtze at the smallish port city of I-ching, he related that "the amount of shipping it carries and the total volume and value of its traffic...exceeds all the rivers of the Christians put together and their seas into the bargain...I have seen in this city fully five thousand ships at once...and there are on (the Yangtze's) banks more than two hundred cities, all having more ships than this."
The national Grand Canal waterway transport network also gave powerful impetus to China's rice-farming revolution (eighth to twelfth centuries), one of the decisive events in Far Eastern history. Originally a dry crop, wet rice had been extensively cultivated in naturally flooded fields alongside the monsoonal rivers of Southeast Asia by small communities since the third millennium BC. It first arrived in China from India around 2000 BC. After about 500 BC more intensive new irrigation methods that allowed cultivation on a larger scale and over a wider range of landscapes began to spread.
Rice irrigation demanded solving formidable water challenges. First, there was the problem of converting nature's hydrological excess of rainfall and floods from an insuperable obstacle into a productive irrigation resource. The transplanted young roots had to be kept submerged in shallow water for several months, after which the water was drained off. Farmers had to prepare, level, and wall the terraced paddies of south China's hillsides, drain and refill paddies at timely moments, and keep the entire system constantly flowing with muddy water in order to provide sufficient oxygen to the rice plants and to suppress infestations of malaria-carrying mosquitoes. A technical array of dams, sluice gates, water-lifting norias, simple treadle pumps, and a network of bamboo pipes enabled the process. The labor was immensely intensive. But so were the rewards. Inundation transformed poor, quickly depleted soils into perennial rice paddies that never had to lay fallow so that yields could sustain population densities far higher than those that could be fed by achievable yields of wheat or maize-thus providing the demographic profile that distinguished Asia's history. In China, it completed a population and dietary transformation that had been evolving gradually over many centuries as many Chinese farmers moved south away from the millet and wheat fields of the Yellow River basin.
China's rice farming revolution reached its apogee in the early eleventh century with the government's importation from Champa in central Vietnam of a variety of rice that matured in only sixty days. The fast-growing Champa rice also required less water than domestic varieties, so it could be grown on drier hillside paddies that soon were irrigated for the first time. In 1012, on the orders of Sung emperor Chen-tseung, samples of the seeds of Champa rice were distributed to farmers in a conscious effort to expand food production. The effects were astonishing. Suddenly, two and three crops could be grown on an expanded area of irrigated land. Rice production soared. China's population promptly followed. By the end of the twelfth century it reached 120 million-double the peak achieved by the Han in AD 2 and the early T'ang in the 700s. Some 75 million lived in the south, inverting the historical population balance favoring the north, and transforming China permanently into a densely populated nation primarily of rice eaters-a profile that defined its economic and social structure until the twenty-first century. Abundant food shipments along the Grand Canal drove the rise of Earth's largest urban centers of the times, cities such as Hangzhou, Kaifeng, Louyang, and Beijing, that also pulsed with resurgent private market commerce and industry. During the Sung dynasty, China's greatest age, these urban centers became hubs of a remarkable scientific renaissance, entrepreneurship, and a protoindustrial revolution six to seven centuries before Europe's. Many great inventions were developed, some which later migrated westward through the Indian Ocean and Silk Road trade routes to stimulate Islamic civilization and later still Europe's rise.
By 1100, China was by far the world's indisputable technological leader. Techniques were being used in smelting iron with coke, canal transportation, bridge design, water-powered textile manufacturing, and producing iron farm tools that were not paralleled in Europe for some 600 years. In addition, China was the first civilization to discover that mixing saltpeter (potassium nitrate) with carbon and sulfur produced a volatile substance that exploded when heated-gunpowder. It also pioneered firearms, scientific instruments for measuring the heavens and navigation, hydraulic clockwork, printed books, moveable type, paper money, and the first toilet paper.
One of the great northern Sung cities, and probably the most important place in the world at the time, was the capital, Kaifeng. In 1100, it was larger than ancient Rome with a registered population plus army of about 1.4 million. Its strategic location near the junction of the Grand Canal and the Yellow River not only put it within easy supply of the rice barges from the south, but also along the water transport routes that brought abundant coal and iron from north China's mines. Kaifeng rose as an important industrial center. Spurred by deforestation which overtook the region by about 1000, Chinese iron smelters had made the breakthrough discovery of how to use coal in place of charcoal to cast iron from coke-burning blast furnaces. They also invented a decarbonization method to produce large quantities of hard steel from cast iron. Iron production soared. By 1078, China was producing 114,000 tons of pig iron, double England's total output 700 years later.
The story was similar in textile manufacturing. Before 1300, China's precocious textile artisans were operating water-powered spinning machines that could draw several silk filaments simultaneously from boiling water-immersed cocoons-some 400 years before England's first water-powered spinners began producing silk stockings in Derby to help launch the industrial factory system. Mechanical clocks, which China invented at least two centuries before Europeans, with sophisticated gearing, precision, and self-regulatory mechanisms, helped government administrators accurately keep the all-important official calendar. The famous 30-foot-tall noria-type water clock, with quarter-hourly gongs and bells, erected in 1090 in a Kaifeng pagoda was even used to calculate favorable heavenly synchronizations of the Chinese emperor's procreation schedule among his 121 wives and concubines.
Yet China's technological leadership did not make it invulnerable to its age-old menace of nomadic invasions from the north. In 1126 the barbarian Ch'in Tartars, armed with iron-weapon-making know-how imported from China and with its traditional, potent cavalry, overran Kaifeng and northern China. They, in turn, were expelled by the Mongols in 1234. The surviving Southern Song dynasty established a new capital at Hangzhou. Utilizing the natural protection afforded by the wide Yangtze River, it built its primary defense around a naval fleet of hundreds of newly designed, armored river- and canal-fighting vessels propelled by paddle wheels and treadmills and armed with onboard projectile-throwing machines, crossbowmen, and pikemen. Behind the Yangtze lay the second line of defense-the muddy rice paddies in which the Mongols' fearsome mounted cavalry bogged down. These defenses helped them survive the onslaught of Genghis Khan's heirs until 1279.