42.
Water development has come much more slowly for two poor rural Kenyan villagers, who in 2004 laid a two-mile-long water pipe that finally brought clean, fresh water to their village from a rural well after a thirty-year wait.
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43.
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44.
Rachel Carson's (43) Silent Spring Silent Spring, highlighting the extensive toxic pollution of waterways, was one of the seminal birth moments of the modern environmental movement. Congress was finally galvanized to enact comprehensive clean water regulations after Cleveland's filthy Cuyahoga River, seen burning in 1952 with industrial pollution (44), again burst into spectacular flames in June 1969.
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45.
Climate change, energy, and food issues are intimately interconnected with water. Retreating mountain glaciers from global warming, such as those that sustain Asia's great rivers and a fourth of humanity, threaten catastrophic droughts and hydroelectricity shortages in the dry season and devastating floods during the monsoons.
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46.
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47.
One fifth of humanity still lacks access to enough clean, fresh water for basic domestic needs and two-fifths for adequate sanitation, compelling hundreds of millions, especially children (46) and women, to forgo education and productive work to walk several miles each day to fetch water for daily survival. Billions in poor regions with inadequate water infrastructure, like Ethiopia's highlands near Lake Tana (47) at the source of the Blue Nile, try to endure water's natural destructive excesses, such as floods, mudslides, and droughts.
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48.
With freshwater use increasing twice as fast as soaring world population growth, a perilous new planetary era of water scarcity is dividing global society and politics between fresh-water Haves and Have-Nots, and establishing a fifth, vital historical use for water-to sustain the earth's lifegiving water ecosystems.
Another major water fragility that undermined Islamic civilization was its shortage of small rivers. Islam's "stream deficit" not only inhibited its development of a speedy, safe, and extensive internal transport network. It also handicapped Islam in exploiting one of the rising sources of potential competitive advantage during the Middle Ages-waterpower. Although Muslim hydraulic engineering knowledge was more advanced than in Europe, the waterwheel never played as important a role simply because of its natural shortage of fast-flowing streams. At a time when rival Europe was learning to apply the abundant waterpower and transport potential of its many small rivers to the development of the early industry that helped drive its historical ascendancy, Islamic Spain continued to use the waterwheel almost exclusively for grinding grain and lifting water. The use of energy derived from waterpower was a seminal factor in the development of early industry. By the mid-twelfth century, Europeans had already attained parity with Islam in waterpower.
Islam's inability to maintain its early command of the high seas was also another key factor in its rapid decline after the twelfth century. In hindsight, the first mortal blow was its failure to defeat Constantinople in 718 and thus monopolize the Mediterranean as an Islamic Lake. This left the door open for European maritime states to build up their sea power. By the late eleventh century, they began to take over the key trade routes. Gradual expulsion from Mediterranean sea trade eliminated a major source of wealth and forced Islamic civilization to rely more extensively on its water-scarce, desert resources and propelled the abruptness of Islam's reversal of fortune.
Yet Islam also failed to fully consolidate its greatest opportunity of all-its control of the rich, long-distance Indian Ocean trade. In the Indian Ocean, the Muslims proved to be timid, shore-hugging sailors. They ventured into the open seas only when absolutely necessary. Nor were they intrepid explorers of the unknown. In Africa they traveled south as far as the treacherous Mozambique Channel between the mainland and the large island of Madagascar, but no farther. Ironically, the channel became known in Arab history as "the passage of the Franks" through which the Europeans-whom the Muslims called "Franks"-sailed when they transformed history by rounding the cape of south Africa and bursting into the Indian Ocean at the end of the fifteenth century. Why Muslim seamen already preeminent in those waters did not try to push on around the African cape into the Atlantic long before Europeans made the breakthrough voyage in the opposite direction may appear in hindsight to be one of world history's great missed strategic opportunities. Yet, in fact, it was simple enough to understand. They had little economic incentive to do so-they already controlled the most profitable trade routes in the world.
Islam's decline at sea more broadly was due to its failure to transform itself into a true maritime civilization. While it occupied the second frontier of its seas, it never genuinely absorbed it into a dynamic new synthesis with its original desert-borne civilization. Alexandria, despite all the advantages of its wonderful large harbor and its central location at the trade interstices of the Mediterranean and routes east, never became a Muslim Venice. Islam coped with its deficit of streams, good harbors, and dangerous coastlines, but it did not truly overcome it. Culturally, Islam remained fundamentally land-oriented. It thus left itself vulnerable to being outflanked when Christian infidels mounted their great challenge to Islam at sea.
One recurrent lesson of history is that societies that passively live too long off old water engineering accomplishments are routinely overtaken by states and civilizations that find innovative ways to exploit water's ever-evolving balance of challenges and opportunities. Thus Muslims failed to meet the challenges posed, first by Chinese junks and then, after China's voluntary withdrawal from the seas, by the spectacular entrance in early 1498 of the Portuguese explorer Vasco da Gama into the Indian Ocean. As often is the case in hindsight, one civilization seems to surpass another, as Muslims did in displacing the Byzantines and Persians, with startling abruptness because advantages have been quietly building up for some time and then express themselves with full force all at once. Advances in navigation, shipbuilding, and sea weaponry had been steadily expanding the opportunities for cheaper, quicker, and safer sea transport and trade. But the ascendancy of sea power was not awesomely displayed until the moment da Gama's fleet rounded Africa's cape and crossed the Indian Ocean and pulled into the port at Calicut, India. In little more than a decade, sturdy Portuguese ocean vessels, armed with cannons that had an effective range of 200 yards, seized control of the Muslims' richest sea routes across the Indian Ocean to the Spice Islands. Portugal's opening of the all-water spice route to India also broke the long-standing Venice-Alexandria stranglehold on the trade of oriental goods throughout the Mediterranean. Venetian overtures to Egypt's rulers to reopen Pharaoh Neko's old Red-Sea-to-Nile "Suez" canal route as a countermeasure came to nought. As a result, the traditional overland camel and sea caravan routes that had yielded so much of Islam's wealth went into accelerated, lasting decline.
Sea power also emerged as the weakest link of Islam's militant revival under the Turks from the fifteenth century. The Turks were originally Far Eastern nomadic steppe cousins of the Mongols. Between the ninth and eleventh centuries, many Turkish tribes entered Islamic territories in the Middle East and converted to Islam, often serving as mercenary soldiers. Over time they became the military backbone, and then the political masters, of Islam. When the era of Mongol hegemony ended, the Ottoman Turks embarked on a military expansion into the Anatolian highlands of modern Turkey.
In 1453, Turks under the command of the young Mehmet II, thereafter "the Conqueror," sent a shudder through all European Christendom by finally taking Constantinople and making it their new capital. The final assault against the historic city was won with the help of a gigantic cannon built by a Hungarian engineer and by Mehmet's own master stroke against the nearly impregnable Golden Horn. His forces dragged 70 galleys overland and launched them behind the Byzantine imperial squadron guarding the Horn's entrance. For the next 200 years, the Turks spearheaded a new Islamic jihad against Christian Europe. In the sixteenth century formidable Turkish Islamic armies stormed through Greece, the Balkans, and Hungary and in 1529 laid siege to Vienna on the Danube in central Europe. During the peak of their power under Sultan Suleyman the Magnificent, who ruled from 1520 to 1566, even Rome itself felt threatened. As late as 1683 Turkish armies were capable of besieging Vienna a second time.
Europe had reacted to the first Arab-led Islamic expansion by launching the Crusades to retake the Holy Land; its response to the Turkish-led second clash of civilizations included a series of sea battles for control of the Mediterranean. Although the Turks' new fleets had reestablished Muslim sea power and had captured the strategic eastern Mediterranean island of Cyprus in 15701571, the Turkmen were no match for European vessels, sailing skills, and naval tactics developed in rough gales and currents of the Atlantic Ocean. In 1541, Lufti Pasha, a former grand vizier to Suleyman, became concerned that while the Ottomans were powerful on land, they were vulnerable to their Christian enemies at sea. His assessment was proven correct in the climactic sea battle between the combined fleets of Christendom and the Turks on October 7, 1571, off the Greek coast at Lepanto, not far from the site of the Battle of Actium that had ended Rome's civil wars. The bloody, four hour Battle of Lepanto is celebrated not just for signaling Christian Europe's decisive triumph over resurgent Islam at sea, but also for marking a turning point in the history of naval warfare-it was the first major sea battle in which gunpowder was important. The Turkmen fought mainly the way most major sea battles had been fought since antiquity-they tried to re-create the conditions of a land battle aboard ship. Their soldiers were armed mainly with bows and arrows and swords for close combat; their pilots and oarsmen tried to ram their galleys into enemy vessels or maneuver them alongside close enough for grappling hooks to draw them together to permit boarding and hand-to-hand fighting. The Christian fleets, by contrast, fought with weapons that presaged the dawning new era of naval warfare. Their galleys had cannons mounted on their bows and their soldiers were armed with muskets or arquebuses that could fire at and hit the enemy from a distance. The Venetians also unveiled an entirely new class of warship, a galleass, that was much bigger than traditional galleys, with 50-foot oars manned by half a dozen men, and large swivel guns. History's next great sea battle, the British defeat of the Spanish Armada seventeen years later in 1588, would complete the transformation to modern artillery-based sea warfare from a distance. At Lepanto, a total of 30,000 men died in the Christians' bloody victory over Islam. Among the Christian wounded was Miguel Cervantes, the author of the novel Don Quixote, Don Quixote, who through his life proudly displayed his maimed left hand as proof of his role in the battle. Lepanto crippled the expansionist ambitions of the Turkish Empire by curtailing its mobility at sea and its access to the vital resources that moved along the world's sea-lanes. who through his life proudly displayed his maimed left hand as proof of his role in the battle. Lepanto crippled the expansionist ambitions of the Turkish Empire by curtailing its mobility at sea and its access to the vital resources that moved along the world's sea-lanes.
The sea battle with Europe illustrated that Islam's demise from international preeminence was only partly due to its own absolute response to its internal water resource fragilities. What its neighbors were doing with their water resources determined outcomes too. Civilizations' responses to their water challenges throughout history were variable and always in flux. Some civilizations rose sooner because water conditions in their habitat were more favorable to being exploited by available technologies and forms of organization. Hydraulic civilizations, for instance, arose earliest because semiarid, flooding river valleys offered opportunities for irrigation they had the ready means to exploit. The development of Islam's trade, using camels to carry goods through its harsher desert habitat, took much longer. Still other regions with even more inauspicious water resource endowments faced challenges so daunting as to all but relegate their native societies to subordinated starting positions in the ongoing competition among societies.
Such was the destiny of much of sub-Saharan Africa, where geography presented formidable hurdles. Its equatorial rain forest regions, like tropical lowlands everywhere, were ecologically precarious habitats particularly inimical to the development of large, advanced civilizations. Its soils were permanently saturated sponges, extremely difficult to clear for farming and unhealthy for human settlement. Travel was hard, except by river. Nonetheless, impressive civilizations did develop in the surrounding drier, more hospitable tropical forests and transitional savanna lands, such as the successive empires that flourished around the Niger River and the headwaters of the Senegal and Gambia rivers. But for a long time these civilizations developed in isolation behind the barrier of large deserts and the impenetrable ocean that limited their ability to engage on equal terms with other societies in the cultural and economic exchange that has stimulated civilization in every age. It was not surprising that the external barriers of sub-Saharan African empires were breeched first by neighboring civilizations propelled by superior competitive advantages in water technology-camel caravans by Arab traders and later by the oceangoing vessels of the Europeans. Following international history's inexorable progression from trade to raid and domination, the Muslims and Europeans pressed their advantages by imposing exploitative relationships upon Africans through trade, conquest, and colonization. The ultimate symbol of this inequity was the large slave trade in black human beings. For centuries this was a monopoly of the Arabs. But when European ships appeared on the Atlantic coast of Africa and offered cheaper and safer sea routes, as well as new markets in the New World, domination of the slave trade shifted from the Arabs to the Europeans.
The Europeans on the ocean-bounded, cold, and wet northwestern edge of the civilized Old World had also inherited water resources that were extremely challenging to tap and harness. For millennia non-Mediterranean northern Europe remained an impoverished backwater. But when its inhabitants finally broke out of the ocean-bound confines of their peninsula-shaped continent with the innovation of open sea sailing, they gained command over one of the most dynamic water advantages in all world history. For much of previous history, sea power mainly had helped small states survive defensively against much larger land-based states with powerful armies; naval prowess equalized the balance of power by enlisting the formidable difficulty of navigating the sea itself into the battlefield, and by stretching and harassing enemy supply lines. But with the advent of open sea sailing, control of the oceanic highways of the entire world suddenly was transformed into an overwhelming offensive advantage. With China's voluntary turn inward and propelled by their leadership at sea, Europeans were able to exert an extraordinary, global dominance that was to last half a millennium.
PART II.
Water and the Ascendancy of the West
CHAPTER SEVEN.
Waterwheel, Plow, Cargo Ship, and the Awakening of Europe While the glory of Chinese and Islamic civilizations waned during late medieval times, another civilization was starting to flourish on the European edge of the Old World. Invigorated culturally by its synthesis of Christian religion with its rediscovered Hellenic-Roman roots, and economically by the fusion of the disparate resources of its precocious, semiarid Mediterranean south and its slower rising, colder, temperate north, Western civilization would consolidate an unprecedented 500-year supremacy over the world's wealth and political order. An ongoing series of water challenges and responses marked the path of Europe's historical ascent. Time and again, water's inherent, latent potency as a transforming agent was unleashed by the conversion of a formidable water obstacle into a vehicle of productive expansion. Most dramatically, the West was propelled by two key turning points in history-the advent of transoceanic sailing with long-range cannonry in the European Voyages of Discovery in the late fifteenth and early sixteenth centuries, and the gradual harnessing of waterpower for industry, first with waterwheels and, in the late eighteenth century, with the invention of the modern steam engine. Also driving the West's rise was the distinctive political economic order that arose in its most dynamic centers, featuring self-expansive, flourishing free markets and representative liberal democracies that sprung from the seeds originally planted by ancient Greece's seafaring city-states.
The European continent's geographic shape as a peninsula bounded on three sides by high seas-the warm, lakelike Mediterranean Sea to the south; the cold, rough, semienclosed North and Baltic seas in the lonely north; and in the west, the vast, stormy, tide-tossed Atlantic Ocean, for most of history at once the West's great impenetrable frontier and its protective barrier-fostered a natural maritime orientation central to its history. The continent's absence of a unifying, arterial inland waterway like Egypt's Nile or China's Grand Canal further pushed Europe's inhabitants toward its seascapes to communicate and trade among themselves. The Danube and Rhine rivers, which might have served as some part of that unifying backbone, flowed respectively east to the Black Sea and north toward the North Sea, both away from the main direction of early civilized European society in the Mediterranean; in fact the two great rivers had provided Rome's primary defensive barrier against incursions from the nomadic barbarians who lived beyond it in the northeast-they were Rome's Great Wall of China. Indeed, just as centralized, large hydraulic civilizations emerged along the arterial, irrigable rivers of some of antiquity's semiarid habitats, Europe's greater reliance on wide seas, rain-fed farming, and many small, navigable rivers helped foster its own distinctive political history of small, competing states linked by markets and friendly to the gradual development of liberal democracies.
Backward northern Europe originally sprang to life during the so-called Dark Ages from about AD 600 to 1000 from a sparsely populated, barbarian hinterland of the old Roman Empire into a settled, autonomously growing region of Christian civilization with critical impetus from a combination of water engineering including new plow technology, land drainage that expanded its rain-fed cropland, and exploitation of its small rivers for navigation and waterpower. Following the Byzantine emperor Justinian's failed bid in the sixth century to reconquer the Roman heartland, northern Europe on both sides of the Rhine and Danube underwent tumultuous centuries of power struggles among barbarians and settled societies from which ultimately emerged a decentralized feudal political system and manorial economy linked by independent walled towns and unregulated trade. The most important barbarian kingdom was that of the Franks, whose conversion to Christianity at the end of the fifth century and political alliance with the Roman papacy was crucial to the survival and spread of the Latin church. At their zenith under Charlemagne, who was crowned Holy Roman Emperor on Christmas Day 800 by Pope Leo III at St. Peter's, the Rhine Valleycentered Frankish kingdoms controlled almost all of modern France and modern Germany, the upper Danube, and northern Italy.
Europe & Selected Medieval Sea Trade Routes [image]
Yet in the ninth and tenth centuries, the stability of the Frankish and other consolidated administrations eroded under pressure from a new wave of barbarian raiders, including the terrifying Scandinavian Norsemen, or Vikings, who earned a living sailing up and down Europe's rivers and coasts in their long, shallow ships by raiding and exacting tribute from settlements situated along the shores. Ultimately repelled by walled citadels and castles defended by mounted, armor-clad knights, these barbarians, too, settled down to civilized life, adopted Christianity and, like converted barbarians throughout history, invigorated their new religion with fresh zeal. The Norsemen who settled in Normandy became the Normans that conquered England in 1066 and soon thereafter provided the knights who seized Sicily from Muslim control and then led the first crusaders from 1096 to 1099 in taking Jerusalem and the Holy Land for Christendom. By about AD 1000 most of northern Europe had been Christianized, and market forces had gained enough momentum to help launch the early stages of the commercial revolution from 950 to 1350 that propelled the West's early economic takeoff.
Northern Europe had always possessed promising physical attributes for development. Thanks to the blessing of the warm, Atlantic Ocean Gulf Stream current from the Caribbean, its northwest was a temperate climate zone suitable for nearly year-round farming despite its subarctic latitudes. It was rich in freshwater and other natural resources, had copious rainfall, and almost endless, indented sea coastlines with many good, natural harbors for shipping and trade. It had the potential backbone of an extensive waterway transport network in its many long, navigable rivers, mostly flowing north, that reached much farther inland than the rivers of Mediterranean Europe.
Yet throughout Roman times the region faced one insuperable water obstacle to agricultural expansion-excessive precipitation and poor natural drainage of its heavy, clay soils. Thick forest and swamps covered most of its flat, often-waterlogged plains. Tillage methods applied in the lighter, drier soils of the Mediterranean and Middle East, notably including the simple wooden, shallow, scratch plow pulled by an ox or pair of asses, were all but useless in the northern terrain. As a result, northern Europe's rain-fed cropland was limited to the slash and burn methods of hillside patches where drainage was adequate and in the few other locations where soils were naturally more permeable and could be worked by laborious, small-scale farming methods. With agriculture perennially hovering around near-starvation levels, population in the region was low and life spans short.
The seminal breakthrough of the agricultural revolution that stirred northern Europe's economic awakening came with the heavy wheeled moldboard plow. Pulled by a team of four to eight oxen, the moldboard plow had deep, curved iron or iron-covered blades that turned over deep furrows and produced high dirt ridges unlocking the fertility of the heavy soils over a wide expanse. The key technical breakthrough besides the application of costly iron blades was the placement between the team and the plowshare of wheels, which acted as a fulcrum for applying greater pressure to the heavier plowshare and improved the machine's mobility over uneven terrain. By the tenth century it was in widespread use everywhere across northern Europe.
Northern Europe's landscape was dramatically transformed. Forests were felled, swamplands were drained, and everywhere wilderness was converted to arable cropland. The intensification of water management wrought by the heavy moldboard plow extended the footprint of mankind's intensively cultivated cropland to new climate zone and sustained one of history's great expansions of farming on rain-fed lands. Agricultural production and productivity both soared, setting the basis for an agricultural revolution that reached its apex in the eleventh to thirteenth centuries. Notably drier and milder climate-1 to 2 degrees centigrade-in Europe from the mid-eighth to thirteenth centuries abetted the expansion. The proof of its great impact was a surge in European population, which more than doubled from AD 700 to 1200 to 6070 million. Population density increased wherever the moldboard plow came into widespread use.
The moldboard plow also acted as a major catalyst in the structural transformation of medieval economic society. Being a powerful, but costly implement, it encouraged the cultivation of larger fields, the collective sharing of scarce draft animals, and cooperative labor among farmers. Fences separating individually owned fields came down and the collectively managed land came to be governed by peasant village councils-an early form of representative democracy-that settled disputes and rendered executive decisions about total cropland management. These councils became essential features of northern Europe's characteristic self-sufficient and self-contained village communities, or manors, which contrasted distinctively from the individualistic economic and social structures that prevailed in the scratch-plowing, drier lands south of the Loire River and the Alps.
The heavy moldboard plow became the foundation of a new three-field triennial crop rotation system that originated in northern France in the ninth century and within three centuries was common throughout northwestern Europe. Wheat or rye was planted in one of three fields surrounding the village in the autumn; the second field was planted in the spring with oats, barley, or peas; the third was left fallow in order to replenish the fertility of the soil. Farming villages often encompassed the cultivated landholdings of free peasants as well as tenant-farmers working part of the lord's manorial domain. The lord provided many general services, such as blacksmithing and the waterwheel-powered gristmill for grinding grain into flour to make the daily bread; tenant-farmers commonly were obligated to use the manorial mill for a standard one-thirteenth share of their grain or flour. The village-centric, manorial economy was integrated into the decentralized, governing feudal association of lords, vassals, knights, and peasants to constitute the signature political economic system of the era.
The agriculture bounty and population growth unlocked from Europe's waterlogged plains by the moldboard plow helped activate other of the region's latent water assets to impel further economic expansion. After 1000, Europe's long inland rivers and northern seacoasts came alive with merchant vessels, often heavily armed, transporting crops and raw material goods like timber, metals, wax, furs, wool, and eventually salted herring, among rising free commercial towns and seasonal trade fairs. On the northern seas, many of these early merchants were descendants of the longboat Norse raiders.
Major advances in the flat-bottomed cog from the eleventh century transformed the treacherous, lonely northern seas into active trade highways carrying bulk cargo with small crews of 20 or fewer. The new cog was a much larger, sturdier single-square sail vessel with a rounded bottom and an innovative central sternpost rudder that replaced the traditional long steering oar. Cargo carrying capacity of the largest cogs sextupled, reaching 300 tons by the late twelfth century. When lofty platforms for archers were added, the high-decked cog also proved to be an excellent warship. Armed convoys of cogs became the workhorse of an informal network of free German seaport cities that by the twelfth century had started to dominate sea commerce in the Baltic and North seas. Centered in Lubeck on the Baltic side of the neck of land dividing the two seas, the powerful German-centered Hansa commercial association (also known as the Hanseatic League), with its own governing membership, laws, and customs, eventually numbered almost 200 free-trading cities and towns. The Hansa domain stretched the breadth of the northern seacoast and, as inland river trade developed, up the Rhine as well. One late-joining Hansa member was Cologne, situated at the juncture of two Rhine waterways, one flowing upstream and the other downstream, and a major overland route. This intersection made Cologne Germany's largest town, albeit with a modest 20,000 inhabitants, in the fifteenth century.
Although always smaller in volume than its sea trade, northern Europe's inland river commerce created an extensive, inexpensive waterway network that galvanized economic activity in much the same manner, although to a far-lesser degree, as the Grand Canal in China. Localities built and maintained flood levees and interconnecting transport canals. In the Low Countries of modern Holland and Belgium, where extensive cropland was reclaimed by drainage, some 85 percent of commercial traffic moved by water, abetted by the use of navigation weirs and, from the late fourteenth century, canal locks. Rivermen often poled their boats downstream on busy rivers, sometimes paying exorbitant tolls for the chains stretching across them to be lowered, much like modern auto tollgates on a highway.
Buoyed by trade and agricultural bounty, the quickening economic pace expanded northern Europe's wealth to levels that eventually surpassed those of the older centers of Mediterranean Europe, which were concurrently undergoing their own commercial upswing impelled by private merchants and market economic forces. "Commerce between the tenth century and the fourteenth century became the most dynamic sector of the economy in country after country, and merchants were the main promoters of change," writes historian Robert S. Lopez. The Commercial Revolution gradually eroded the controlling power "of landowners and officials and made the market, instead of the public place or the cathedral squares, the main focus of urban life."
Urban hubs throbbing with new market activity rose to prominence starting in the eleventh and twelfth centuries. Wherever navigable waterways converged or where key river crossing or favorable harbors were established, influential urban commercial centers arose. The most vibrant cluster in northern Europe was in the Low Countries, where the navigable Rhine, Meuse, and Scheldt rivers flowed near one another. It included the ports of Ghent, the largest city with 50,000 inhabitants in the fourteenth century, Bruges, Antwerp, and later Amsterdam; other big centers included Lubeck, London, and Paris. This was mirrored in Mediterranean Europe by a cluster of large northern Italian city-states, above all Venice, Genoa, Milan, and Florence, with populations surpassing 100,000.
Due to the overriding importance of water navigation, it was no accident that the central marketplaces of Europe's Commercial Revolution developed literally on top of and alongside the bridges and quays of the leading medieval towns and city-states. Like towns, bridges underwent a major building boom from the eleventh to thirteenth centuries, often becoming each town's pulsing central marketplace. Shops and houses located around the bridges enjoyed the further medieval privilege of having at hand a common drinking water and sewage disposal source in the river below. Crowded with shops and markets were the late twelfth-century Old London Bridge across the Thames, the Grand Pont across the Seine, also featuring 13 floating water mills moored below its arches where the river flowed fastest to produce fourteenth-century Paris's daily bread flour, and the stone bridge that still crosses the Arno at Florence, the Ponte Vecchio. Many pioneering early bridges were built by monastic orders, including the famous, 20-arched, Pont d'Avignon across the notoriously flooding Rhone in southern France that was erected in the late twelfth century by the Freres Pontifes, (Brothers of the Bridge). As bridges became a practical amenity that enhanced town trade and commerce, civic authorities undertook the responsibility for building many of them. This helped revive the Roman practice of public infrastructure investment, which became a mainstay of the West's liberal, democratizing marriage of convenience between governments and private markets.
Few bridges were at the center of so much important medieval commerce as Venice's Rialto Bridge, the lone crossing over the Grand Canal at the heart of the greatest Mediterranean sea trading power of the age. The first wooden Rialto Bridge was built in 1264, replacing an old pontoon crossing. Several wooden iterations later, the late sixteenth-century stone bridge was erected, crammed then as today with two arcades of noisy shops and businesses bustling along its banks. Bakers, butchers, fishmongers, fruit and vegetable sellers, acrobats and other entertainers, and even the infirm in their beds at the hospice were conspicuous daily sights. Upon closer look, the hierarchical skeleton structure of early market capitalism itself was physically visible beneath the manifold relationships of the merchants of Venice crowded around the Rialto: the small merchants haggling over price and exchanging goods for money on the bridge within earshot of the larger wholesale suppliers who bought, sold, and signed trade and shipping contracts every morning nearby in their loggia, or meeting room-an early commodities exchange-and who then later in the day walked a few paces to the narrow bank counter stalls of the banchieri banchieri-the "bankers"-who settled their transactions by book entry account fund transfers and reinvested the accumulated capital profits of the marketplace in a new circuit of loans and ownership stakes in fresh speculative ventures. Many modern financial practices began in this era, including the debit and credit and double-entry format of modern balance sheet accounting and, in the fourteenth century, the bill of exchange facilitating merchants' ability to conduct business in distant locations. The era also inaugurated history's notable sovereign loan defaults-by British monarchs to their Italian bankers-with the resultant bank collapses and international financial and economic crises.
For centuries the two distinctive, rival economic realms of town commerce organized by market supply and demand on the one hand, and the immense, traditional manorial economy of barter and self-sufficient farming on the other, coexisted side by side with overlapping trade between them. Gradually, however, the more-productive market realm expanded faster and brought more and more of Europe's economic resources under its ambit, eventually relegating the manorial realm to the margins, and then the annals, of history. Enough development had occurred before the disruptive, population-decimating famines and plagues of the fourteenth century that the outline of Europe's signature model of market economies operating across a fragmented political environment was visibly emerging.
The superior competitive dynamism of the town over the manorial realm in shaping Europe's destiny was vividly illustrated by their contrasting uses of the waterwheel. On the manor, the waterwheel rarely transcended its traditional function for grinding grain into flour. Under the influence of commercial market forces centered in the towns, it was transformed into a primary agent of the Mechanical Revolution (eleventh to thirteenth centuries) that powered the takeoff of Europe's early industries.
The waterwheel's invention in the first centuries before the Christian era ranked as one of the watershed moments in the history of civilization. In contrast to its older cousin, the ancient, animal-powered noria, or wheel of pots, that lifted water mainly to irrigate cropland, waterwheels fitted with paddles or blades turned automatically in ceaselessly flowing currents to transmit the captured water flow energy to do productive work. In effect, the waterwheel was history's first mechanical engine. It provided mankind with its first great breakthrough in harnessing an inanimate force of nature since the domestication of fire at the dawn of humanity and sailing at history's early beginnings. For some two millennia waterpower would represent the pinnacle of civilization's constructive command of nature's power.
The simple horizontal waterwheel-in which water flow turned a wheel that lay parallel with the millstone affixed above it-was used the world over, chiefly to grind bread flour. It was several times more powerful than the ancient hand mill turned at about one-half horsepower by two slaves or a donkey. Horsepower was augmented by a factor of five to six times over the hand mill by the innovation of placing the wheel vertically in the water. The vertical undershot wheel transmitted its rotating power through a camshaft and gearing mechanisms to turn multiple millstones or other devices at higher speeds of rotation, even though its reliability varied with fluctuating stream and weather conditions, such as droughts, floods, and freezes. Another major improvement-which became crucial to launching Europe's early industrial development in the late Middle Ages-was an overshot version of the vertical waterwheel. By directing a steady flow of water to fall onto the wheel blades from above, often through a millrace emanating from an artificial pond or a dammed river and regulated by a sluice gate, the vertical overshot wheel typically was three to five times more efficient than its undershot cousin and also permitted larger, more-powerful wheels to be employed. Leonardo da Vinci, who worked brilliantly on many problems of water hydraulics including canal locks, water pumps, bridges, and paddleboats as well as waterwheels, was among the earliest to argue, rightly, that the overshot wheel was the most efficient design some 250 years before engineers were able to prove why. A few exceptional overshot wheels in medieval Europe were capable of as much as 40 to 60 horsepower. Coastal regions from Venice to Brittany and Dover even experimented with ocean-tide-powered mills, although these always remained on the periphery of mainstream waterpower history.
Although ubiquitous, waterwheels until the eleventh century were commonly weak in individual horsepower and rarely used for industrial applications. The Domesday Book (1086), compiled by Britain's new Norman rulers to assess what potentially taxable assets they'd won in their conquest of 1066, recorded that south of the Severn and Trent rivers there were no less than 5,624 mills serving 3,000 settlements-or nearly two water mills per settlement. The ratio was likely similar on the even more prosperous and heavily populated Continent. Mills were widespread enough to have been taxed by Charlemagne at the start of the ninth century. Damming rivers to power waterwheels is recorded in the annals of French history from the twelfth century, with one account describing how a king hastened the surrender of a town he was besieging by breaking the dams that powered its mills. In the early fourteenth century, the Seine near Paris had 68 mills concentrated within less than one mile. Floating mills were common sights under the bridges of major cities. Virtually every suitable little stream in inhabited regions had several flour mills, often situated every quarter to half mile apart. By the debut of the eighteenth-century Industrial Revolution, Europe likely had over half a million water mills, whose enormous combined horsepower provided an indicative proxy for the advanced stage of material civilization attained in the West.
The waterwheel's greatest impact on world history was in Europe because it was there that it was most extensively applied to early industry, especially after the eleventh century. The waterwheel inspired experimentation by craftsmen with a panoply of mechanical gears, flywheels, camshafts, conveyor belts, pulleys, shifters, and pistons that seeded the foundational know-how of industrial production. The surprising technological pioneers of applying waterpower to industry were religious monasteries. Ever since St. Benedict foreswore his solitary hermit's existence and instituted the Benedictine Rule for the monastic community he established in AD 529 at Monte Cassino in southern Italy, European monks had been actively engaged in physical labor as a material and spiritual boon to their communities' purpose. Self-sufficient monastic communities played a key role in early medieval civilization by preserving ancient books and rekindling classical learning, converting pagans to Christianity and less famously, advancing and disseminating many hydraulic arts, including dike building and maintenance, swamp drainage, and bridge building, as well as the application of waterpower to myriad monastic activities.