Cathedral, Forge, and Waterwheel Part 3

These fortresses were not, however, the last word in castle architecture. The advance to the final stage resulted in no small measure from the First Crusade. By leaving a few thousand knights and men-at-arms marooned in Syria and Palestine amid a sea of hostile Saracens, the Crusade placed a tremendous burden on defensive fortifications. Enriching their own European experience with ideas borrowed from the enemy-entrance traps, concentric walls, inner keeps76-the Crusading orders of the Templars and Hospitalers lined the frontiers of Syria and Palestine with castles that were the engineering marvels of the age, sometimes built from scratch, sometimes by enlarging, repairing, and elaborating captured Arab fortresses. Where earlier castle builders in Europe had paid scant attention to terrain, the Crusader castles were carefully sited on high ground, their few approaches cleared of cover and broken by a deep ditch (the moat). The corners of the rectangular keep were vulnerable to sappers digging under them and offered "dead ground" for attackers armed with battering rams to shelter out of reach of the garrison's missiles; the Crusading castles, copying Byzantine and Saracen models, gave their corners round or multisided towers that effectively resisted both threats.77 The main line of defense of the new castle was its high curtain wall, whose parapet was protected by crenellated battlements and provided with machicolations, another borrowing from the Arab enemy-openings in the floor through which missiles and boiling liquids could be dropped. Firing windows, called "arrow loops" or meurtrieres meurtrieres (murderesses) were flared to the inside, giving the defending archer room to move laterally, with a wide field of fire, while presenting to the besieger only a narrow exterior slit as a target. (murderesses) were flared to the inside, giving the defending archer room to move laterally, with a wide field of fire, while presenting to the besieger only a narrow exterior slit as a target.

Crenellated curtain wall, with machicolations-openings through which missiles could be dropped. Fougeres, Brittany.

Entry to the castle was through a gatehouse, whose portcullis, oak plated and shod with iron, was raised vertically by a pulley operated from an upper chamber in the gatehouse. Spanning the moat was a bridge with a draw section operated by counterweight. A device unknown to the Romans, the drawbridge was forgotten after the Middle Ages until revived by nineteenth-century bridge engineers for its modern purpose of spanning busy waterways. Sometimes the entry was through a skewed pa.s.sage where infiltrators might find themselves trapped under fire from archers above them. If the outer wall was breached, the defenders could still fall back to the inner keep, with its own well-planned fields of fire.

A firing window or arrow loop flared to the inside (with late modification for guns). Falaise, Normandy.

The most famous of all the twelfth-century castles in Europe and Syria was the Krak des Chevaliers (Citadel of the Knights). Built by the Hospitalers in the first half of the twelfth century on the spur of a mountain, its ma.s.sive walls formed two concentric rings dominated by great towers and separated by a wide moat. In addition to meurtrieres meurtrieres, crenellations, and machicolations, the castle's walls bore a less ferocious piece of technology, a windmill to grind the garrison's grain.78 Besieged at least a dozen times, the Krak resisted every a.s.sault and continued to "stick like a bone in the very throat" of the Saracens, in the words of a Muslim writer, Besieged at least a dozen times, the Krak resisted every a.s.sault and continued to "stick like a bone in the very throat" of the Saracens, in the words of a Muslim writer,79 until in 1271, one of the last European strongholds in Asia Minor, it was captured by a ruse. The Muslim general Baibars tricked the garrison with a forged order and afterward chivalrously provided them with safe-conduct to the coast. until in 1271, one of the last European strongholds in Asia Minor, it was captured by a ruse. The Muslim general Baibars tricked the garrison with a forged order and afterward chivalrously provided them with safe-conduct to the coast.80 The Krak des Chevaliers (Citadel of the Knights), Crusader castle in the Holy Land. [From Kenneth M. Setton, ed., A History of the Crusades, University of Wisconsin Press.] University of Wisconsin Press.]

The living quarters of twelfth-century castles featured a device that was immediately and widely copied: the wall fireplace. A marked improvement in efficiency over the old central hearth, the fireplace provided heat both directly and by radiation from its own stones and from the wall opposite. Late in the century, a projecting hood was added to better control the smoke, and the sides of the hearth were splayed to increase radiation. Whether in a castle or in a house, the fireplace was immense by modern standards, designed to accommodate large, long-burning logs.81 Despite their size and complexity, castles were often built with impressive speed if the need was urgent and the financial resources were available. Richard Lionheart's Chateau Gaillard on the Seine was essentially built in a single year.82 Wall fireplace in great hall of the early-twelfth-century square keep at Vire, Normandy.

To attack or defend a castle, missile weapons were indispensable, and the period that initiated the building of castles also saw the introduction of a new form of artillery. A version of the trebuchet employing human traction to power the firing beam was invented in China as early as the first century A.D. A.D. and possibly pa.s.sed via the Turks to the Arabs and Byzantines. and possibly pa.s.sed via the Turks to the Arabs and Byzantines.83 Whether Parisians employed it against the besieging Vikings in the ninth century is a minor scholarly controversy. In the period between 1180 and 1220, the trebuchet was given a decisive improvement in Europe by the subst.i.tution of a huge counterweight for the manpower brigade. The machine's arm was mounted asymmetrically on a fulcrum, with the short end, pointing toward the target, given the counterweight. The long end, wound back by a winch, was released by a blow from a mallet. The missile was carried in a sling, attached by long lines and lying at rest in a trough under the machine; when triggered, the beam sprang upward through an arc, gaining acceleration before the missile was picked up. Consequently, high "muzzle velocity" could be achieved, especially if the missile was released at near the optimum angle of 45 degrees. Whether Parisians employed it against the besieging Vikings in the ninth century is a minor scholarly controversy. In the period between 1180 and 1220, the trebuchet was given a decisive improvement in Europe by the subst.i.tution of a huge counterweight for the manpower brigade. The machine's arm was mounted asymmetrically on a fulcrum, with the short end, pointing toward the target, given the counterweight. The long end, wound back by a winch, was released by a blow from a mallet. The missile was carried in a sling, attached by long lines and lying at rest in a trough under the machine; when triggered, the beam sprang upward through an arc, gaining acceleration before the missile was picked up. Consequently, high "muzzle velocity" could be achieved, especially if the missile was released at near the optimum angle of 45 degrees.

Loading a trebuchet, top left; adjustable counterweights are hidden behind melee at center. [The Pierpont Morgan Library, Maciejowski Bible, M. 638, f. 23r. (detail)]

A vast amount of experimentation, of which no record survives, must have gone into the development of the counterweight trebuchet. The counterweight was in the form of a hopper filled with earth or stone, specified in one source as "nine feet across and twelve feet deep."84 Varying the weight controlled the range. Modern experiments comparing the trebuchet with its ancient forebears have shown the medieval weapon capable of hurling a much larger projectile, a ma.s.s of 100 to 150 kilograms (220 to 330 pounds) a distance of 150 meters (160 yards) Varying the weight controlled the range. Modern experiments comparing the trebuchet with its ancient forebears have shown the medieval weapon capable of hurling a much larger projectile, a ma.s.s of 100 to 150 kilograms (220 to 330 pounds) a distance of 150 meters (160 yards)85 The older catapults have shown greater range, up to 225 meters (245 yards), but only with a much lighter missile, one of 20 to 30 kilograms (44 to 66 pounds). To batter down heavy masonry walls, weight of projectile was much the more important consideration. The value attached to the trebuchet is reflected in the custom of giving each engine a name, such as those recorded for Edward I's siege of Stirling in 1304: Vicar, Parson, War-Wolf, Gloucester, Belfry, Tout-le-monde. The older catapults have shown greater range, up to 225 meters (245 yards), but only with a much lighter missile, one of 20 to 30 kilograms (44 to 66 pounds). To batter down heavy masonry walls, weight of projectile was much the more important consideration. The value attached to the trebuchet is reflected in the custom of giving each engine a name, such as those recorded for Edward I's siege of Stirling in 1304: Vicar, Parson, War-Wolf, Gloucester, Belfry, Tout-le-monde.86 A different version of the same machine, the "mangonel," appearing at the same time, had a lower "angle of departure," giving its missile a flatter parabola. The effectiveness of trebuchet and mangonel is indicated by the absence after the tenth century of references to the old-fas.h.i.+oned torsion engines.87 An even more important missile weapon made its appearance in Italy in the eleventh century. The crossbow had been known to the Romans (and the Chinese) centuries earlier but had never been very effective in its ancient form and had disappeared from warfare. Its basic principle was that a bow set transversely on a stock, or crosspiece, could be bent farther and so develop greater muzzle velocity than a handbow. In its medieval reincarnation, the weapon was c.o.c.ked by resting the bow on the ground with the stock upright; the archer placed his foot in a stirrup on the stock, stooped to catch the bowstring on a hook in his belt, and by straightening up bent the bow, using the strength of his whole upper body instead of merely that of his arm. The bowstring was brought back to a locking device on a groove in the stock and fitted to the bolt, a short, very thick arrow armed with a heavy iron tip.

The crossbow was more expensive than the ordinary bow and took longer to reload, but in castle defense both disadvantages were minimized. The archer could reload in safety, while in the economics of siege warfare, in which a garrison of a hundred was expected to hold out against thousands of attackers, high cost of individual equipment was justified.

An important improvement in the medieval crossbow may have been learned during the Crusades from the Saracen enemy (strangely, the Crusaders' Byzantine allies in 1097 knew nothing of the weapon, which princess-chronicler Anna Comnena described as "a Frankish novelty" and "a truly diabolical machine").88 Wood as bow material was strong in compression but weak in tension, and the outer part of a bent bow was under tension. The tension created by the strength of a man's arm was easily resisted by a strong wood, such as yew. But the tension created by the crossbow's bending could cause "slithers" to splinter away. A strip of animal sinew, usually the large ligament that runs along the spine of most mammals, was incorporated as a reinforcing layer on top of the wood, absorbing some of the tension. Such a "composite" bow was made even stronger by a layer of animal horn on the underside. The power of the new weapon alarmed the Church, which in the Lateran Council of 1139 anathematized its use (and for good measure that of bows in general) against Christians. "Naturally, this prohibition was very unevenly observed" (Philippe Contamine). Wood as bow material was strong in compression but weak in tension, and the outer part of a bent bow was under tension. The tension created by the strength of a man's arm was easily resisted by a strong wood, such as yew. But the tension created by the crossbow's bending could cause "slithers" to splinter away. A strip of animal sinew, usually the large ligament that runs along the spine of most mammals, was incorporated as a reinforcing layer on top of the wood, absorbing some of the tension. Such a "composite" bow was made even stronger by a layer of animal horn on the underside. The power of the new weapon alarmed the Church, which in the Lateran Council of 1139 anathematized its use (and for good measure that of bows in general) against Christians. "Naturally, this prohibition was very unevenly observed" (Philippe Contamine).89 The Brothers of the Bridge Crusaders, pilgrims, and merchants were perpetually on the road, but travel in the age of the Crusades was not for the faint-hearted. A tenth-century wayfarer described his journey from Constantinople to Lepanto, Greece, a distance of some five hundred miles, in these terms: "On mule-back, on foot, on horseback, fasting, suffering from thirst, sighing, weeping, lamenting, I arrived after forty-nine days."90 By that time it was evident that the old Roman road network was out of date as well as out of repair. Its steep grades hindered merchants' carts and pack animals, and its crumbling surfaces challenged even unenc.u.mbered travelers. Many of the routes, designed to serve Roman garrisons, no longer went where people wanted to go, while the new and growing traffic of medieval pilgrims needed roads to places the pagans had never sought to visit-Canterbury, Compostela, Roc Amadour. By that time it was evident that the old Roman road network was out of date as well as out of repair. Its steep grades hindered merchants' carts and pack animals, and its crumbling surfaces challenged even unenc.u.mbered travelers. Many of the routes, designed to serve Roman garrisons, no longer went where people wanted to go, while the new and growing traffic of medieval pilgrims needed roads to places the pagans had never sought to visit-Canterbury, Compostela, Roc Amadour.

As medieval commercial expansion altered the ratio of traffic, wheeled vehicles for the first time demanded a substantial share of the road. Certain kinds of merchandise suffered from rough surfaces. The tight-fitting wooden barrels that had replaced amphorae allowed wine to age properly but were likely to burst under severe jolts.91 How much road construction and maintenance was practiced in the central Middle Ages is unknown, but road builders did develop a surface of cobbles set in a thick cus.h.i.+on of sand that was better adapted to the northern climate than the rigid Roman pavement. As central and regional governments strengthened, roads under royal, imperial, or other seigneurial protection were most likely to receive attention. In England, royal roads were supposed to be maintained at a width sufficient for two wagons to pa.s.s, or for two oxherds to make their goads touch, or for sixteen armed knights to ride side by side. How much road construction and maintenance was practiced in the central Middle Ages is unknown, but road builders did develop a surface of cobbles set in a thick cus.h.i.+on of sand that was better adapted to the northern climate than the rigid Roman pavement. As central and regional governments strengthened, roads under royal, imperial, or other seigneurial protection were most likely to receive attention. In England, royal roads were supposed to be maintained at a width sufficient for two wagons to pa.s.s, or for two oxherds to make their goads touch, or for sixteen armed knights to ride side by side.92 The only road built from scratch under the Norman kings of the eleventh and twelfth centuries was the one cut by Henry I in 1102 for the pa.s.sage of his army over Wenlock Edge. The only road built from scratch under the Norman kings of the eleventh and twelfth centuries was the one cut by Henry I in 1102 for the pa.s.sage of his army over Wenlock Edge.93 By the twelfth century, the horse collar and harness had made the horse much the preferred traction for cart and wagon. Maneuverability was improved by several new or revived features: subst.i.tution of a pair of shafts for the old single draft pole; the whippletree, a transverse bar pivoted in the middle and positioned in front of the wagon (ill.u.s.trated drawing a plow in the Bayeux Tapestry);94 and the pivoted front axle. Nailed horseshoes, common by the eleventh century, were ma.s.s-produced by the twelfth. and the pivoted front axle. Nailed horseshoes, common by the eleventh century, were ma.s.s-produced by the twelfth.95 The spread of stirrups and saddles helped make riding easier and more popular. The spread of stirrups and saddles helped make riding easier and more popular.

In bridge construction, a tenth-century "nadir" (Marjorie Nice Boyer) was followed by a resurgence in the eleventh century.96 The eclipse of the Carolingian monarchy and the inheritance by local lords of the wardens.h.i.+p of river crossings opened up a new chapter in bridge building. Increased volume made toll collection an important source of revenue for many lords, while drawing attention to the inadequacy of ferries, where wagons, pack trains, droves of animals, and troops of the pious queued up to board the skiff or raft. The eclipse of the Carolingian monarchy and the inheritance by local lords of the wardens.h.i.+p of river crossings opened up a new chapter in bridge building. Increased volume made toll collection an important source of revenue for many lords, while drawing attention to the inadequacy of ferries, where wagons, pack trains, droves of animals, and troops of the pious queued up to board the skiff or raft.

The Church intervened. Bishops began granting indulgences for bridge construction and repair, and the monastic orders took to collecting funds as well as maintaining hospices at crossings.97 Bridges also profited from inclusion in legacies, along with churches, hospitals, and "other pious and poor places." Bridges also profited from inclusion in legacies, along with churches, hospitals, and "other pious and poor places."98 In southeastern France in the twelfth century, a new, highly specialized order was founded by an ex-shepherd who became St. Benezet, also known as Little Benedict the Bridgebuilder. The Freres Pontifes, or Brothers of the Bridge, built the Pont d'Avignon, whose twenty arches spanning the Rhone (and the island of Barthela.s.se) were of a new design, credited to Benezet himself: elliptical, with the long axis vertical. The tall arches required less support during construction than the old Roman semicircular arches, permitting narrower piers in the stream. At the same time they provided more room for the rising waters of the notorious Rhone floods. The decrease in constriction reduced scour around the piling that underpinned the piers, the main threat to the stability of stone-arch bridges.99 Remaining four arches of the Pont d'Avignon, over the Rhone, built by the Brothers of the Bridge in the twelfth century. [French Government Tourist Office.]

Pont-St.-Esprit, another Brothers of the Bridge construction, with flattened segmental arches.

Near the Avignon end of his bridge, St. Benezet built a combination of chapel and toll station, mingling piety with practicality in a graceful symbol. The Brothers of the Bridge raised funds and oversaw construction of at least two other large stone-arch bridges, at Lyons and Pont-St.-Esprit. The St. Esprit span introduced a design new to Europe, though long known in China: the flattened segmental arch (based on an arc smaller than a semicircle). The opposite of St. Benezet's tall arch, it was difficult to construct and had been avoided by the conservative Romans, but once in place it derived superior stability from the smaller number of piers in the river and consequent reduction in scour.100 The St. Esprit arches, however, were only slightly flatter than semicircular, and the extent to which the bridge's builders understood the advantage is hard to say. Until the fourteenth century, nearly all medieval bridges continued to employ the semicircular arch. The St. Esprit arches, however, were only slightly flatter than semicircular, and the extent to which the bridge's builders understood the advantage is hard to say. Until the fourteenth century, nearly all medieval bridges continued to employ the semicircular arch.

In the cities medieval bridges increasingly took on the function, unknown to the bridges of Rome, of supporting houses and shops, for which they offered convenience in both water supply and sewage disposal. London Bridge, begun in 1176 by a local chaplain named Peter of Colechurch and partly financed by a thousand-mark gift from the papal legate, became the picturesque heart of the city, its roadway loaded with a double row of structures of varying sizes and purposes. A less sophisticated design than the Pont d'Avignon, London Bridge was supported by nineteen semicircular stone arches, no two quite alike, built summer after summer as money was available, until completion in 1209. Its ma.s.sive piers so constricted the tidal Thames that piloting a boat through at high water became a sporting proposition known as "shooting the bridge." A small draw span, included as a defensive measure, was too narrow to allow most boats to pa.s.s. London boatmen adopted the expedient, quickly copied elsewhere, of removable masts for squeezing under the bridge. But the occasional use of the draw span to pa.s.s narrow-hulled, fixed-mast craft may have been the first application anywhere of the drawbridge to navigation.101 The bridges of Paris: on the Grand Pont, left, a money changer awaits customers, a goldsmith hammers, and a rag-picker carries basket and pick; on the Pet.i.t Pont, right, a doctor gives a prescription in an apothecary shop; on the river below, a fisherman casts his line. [Bibliotheque Nationale, Ms. fr. 2092, f. 35v.]

Construction techniques had changed little from Roman times. The season for work ran generally from mid-June to September-October. The princ.i.p.al machinery used was a ram, a heavy weight raised by windla.s.s or pulley that drove piles, three to four yards long and sharpened at the ends, into the riverbed. The superstructure was often a mixture of stone and wood, the latter chosen with care, with preference for chestnut, which resists rotting and is strong in compression. A roadway might be supported by timber arches sprung from stone piers or by-a combination of stone arches and timber trestle.102 Medieval builders introduced an improvement in the starlings, or cut.w.a.ters, the footings from which the piers rose. Roman starlings were pointed at the upstream end to breast the current but made square downstream. St. Benezet may have been the first to point his downstream starlings, an innovation that reduced eddying and so helped combat scour.103 The Pont d'Avignon stood intact until the seventeenth century, London Bridge until the nineteenth, and the Pont-St. Esprit and several others still stand today. Despite numerous failures from flood, scour, fire, ice floes, and enemy action, medieval bridges may be judged eminently successful solutions to a set of engineering problems under the handicap of existing conditions.

Grain is delivered to floating mills under the Grand Pont in Paris. [Bibliotheque Nationale, Ms. fr. 2092, f. 37v.]

In the teeming walled towns, the bridge was typically the center of activity. A person could be born on a bridge, grow up there, work in his establishment and live upstairs, go to church, shop at the butcher's and baker's, and retire to a hospital for the aged, all without leaving the bridge. In Paris he might enjoy the performances of musicians and acrobats, such as the tightrope walker of 1389 who performed on a wire stretched between a tower of Notre Dame and the tallest house on the Pont-St.-Michel.

Inland waterways, virtually unknown in the ancient world, had their Western beginnings in the Middle Ages.104 To improvement of river navigation by levee building, the eleventh century began adding construction of ca.n.a.ls, for which, however, ca.n.a.l locks remained a Chinese secret. In their place, level-changing stations were created by erecting inclined planes with boat-carrying platforms powered by horse winch. Despite such efforts, the inland waterways carried only a minor part of the growing commercial traffic of the late twelfth century. To improvement of river navigation by levee building, the eleventh century began adding construction of ca.n.a.ls, for which, however, ca.n.a.l locks remained a Chinese secret. In their place, level-changing stations were created by erecting inclined planes with boat-carrying platforms powered by horse winch. Despite such efforts, the inland waterways carried only a minor part of the growing commercial traffic of the late twelfth century.

Cog, Compa.s.s, and Rudder The commercial expansion manifested itself even more conspicuously in seaborne than in overland transportation. s.h.i.+ps, both sail and oar, multiplied in northern as in southern waters. Luxury goods were a prominent part of cargoes, though the term "luxury" meant different things in Europe's two regions. In the north, luxury goods included manufactures of any kind which had to be carried from their specialized places of origin to the rest of the area. In the Mediterranean, manufacture was more widely diffused and for the most part was traded locally; luxury goods here meant primarily the very expensive products of the Far East, laboriously conveyed to the frontiers of Europe by Arab s.h.i.+p and Asian pack train.

The most important eleventh-century development in northern waters was the improvement of the round-hulled cog. The flat bottom that had made the earlier cogs handy for beach landings had also made them p.r.o.ne to leeway-drifting sideways off course. As port facilities multiplied, it became practical to give the cog a round bottom and deep keel, substantially alleviating the problem. Entirely sail propelled, the new model carried a single huge square sail of cotton or linen canvas, roughly 190 square yards in area, which could be augmented in fine weather by the addition of "bonnets," small pieces of canvas attached to the bottom edge. Flexibility was further increased by "reef points," short lengths of rope run through the sail in rows to roll up and tie the shortened canvas. Clinkering was kept but reversed, the bottom plank made to overlap the one above, giving a stronger hull. Freeboard (the side of the hull above water) was high, making the new cog distinctly an open-water overseas trader, economizing on manpower per cargo ton. Where an old-fas.h.i.+oned knorr of the type that colonized Iceland and Greenland could carry 50 tons with a crew of twelve to fourteen, the new cog, with its tublike proportions of a beam one third or more of its length, could carry 200 tons with a crew of eighteen to twenty. By the late twelfth century, cog capacity was reaching 300 tons.105 Boatbuilder's tools: Noah building the ark. [Bodleian Library, Ms. Barlow, f. 53.]

Surprisingly, the cog also proved an excellent wars.h.i.+p and in doing so added a new element to s.h.i.+p structure. The height of its deck made it virtually impregnable to anything but another cog; to match its advantage, Scandinavian longs.h.i.+ps were given "castles," temporary platforms for archers. The cogs' builders promptly added castles to their own vessels, regaining the advantage, and the castle, in bow and stern, soon became a permanent feature.106 Though the oar-propelled longs.h.i.+p could maneuver circles around it, the cog's lofty castles gave its archers a commanding position. Bulky, ungraceful, competent, and formidable, the cog became the workhorse and war-horse of the German Hanseatic cities that by the twelfth century were beginning to dominate Baltic and North Sea commerce. Though the oar-propelled longs.h.i.+p could maneuver circles around it, the cog's lofty castles gave its archers a commanding position. Bulky, ungraceful, competent, and formidable, the cog became the workhorse and war-horse of the German Hanseatic cities that by the twelfth century were beginning to dominate Baltic and North Sea commerce.

In the Mediterranean, too, s.h.i.+p styles evolved with changing conditions. For one thing, a new fas.h.i.+on in piracy emerged. As Muslim nests on the European coast were ferreted out and European ports given stronger defenses, the Arab corsairs turned from amphibious raiding to attacking s.h.i.+ps at sea. The Europeans joined in the game by fitting out privateers of their own and turned attention to making their cargo carriers more defensible. The galleys that specialized in high-value cargoes were made larger, lower, and faster, and Venice pioneered the castle in southern waters. The round sailing s.h.i.+ps were also enlarged. The tideless Mediterranean had always presented problems in beaching s.h.i.+ps for loading and unloading, and as s.h.i.+p size grew, the need for port facilities pressed, stimulating growth of the major port cities-Genoa, Pisa, Venice, Amalfi, and others. Transport of pilgrims and Crusaders and logistical support of the Crusades reinforced the stimulus. "By 1250 most significant ports in both northern and southern seas had at least one [quay]" (Richard Unger).107 Both docks and s.h.i.+ps were made of wood. Venice, with its piers and a.r.s.enal, was the first medieval port to feel the pinch of forest depletion, especially the shortage of certain types of tree: oak for hulls; larch and fir for internal planking, masts, and spars; elm for capstans and mastheads; and walnut for rudders, one of two Chinese inventions that began appearing in the twelfth century.108

Rather surprisingly, the mariner's compa.s.s did not arrive in Europe courtesy of the Arabs, who did not use it for navigation until the thirteenth century. Joseph Needham conjectures that it traveled overland, via the Silk Road, and not in a navigational context but as an astronomical-astrological and surveying instrument.109 In its earliest European form, the compa.s.s followed the Chinese prototype, a magnetized needle transfixed on a straw, reed, or chip of wood floated in a bowl of water. The Chinese also produced a dry suspension, with the needle pivoted on a bamboo pin set in a hole on a small board; a European version, perhaps independently developed, consisted of a circular box with the needle rotating on a vertical pin. In its earliest European form, the compa.s.s followed the Chinese prototype, a magnetized needle transfixed on a straw, reed, or chip of wood floated in a bowl of water. The Chinese also produced a dry suspension, with the needle pivoted on a bamboo pin set in a hole on a small board; a European version, perhaps independently developed, consisted of a circular box with the needle rotating on a vertical pin.

The first Western textual reference to the mariner's compa.s.s occurs, in the twelfth-century English scholar Alexander Neckam's book De naturis rerum De naturis rerum (On the natures of things): "The sailors...when in cloudy weather they can no longer profit by the light of the sun, or when the world is wrapped in the darkness of the shades of night, and they are ignorant as to...their s.h.i.+p's course, they touch the magnet with a needle. This then whirls round in a circle until, when its motion ceases, its point looks direct to the north." (On the natures of things): "The sailors...when in cloudy weather they can no longer profit by the light of the sun, or when the world is wrapped in the darkness of the shades of night, and they are ignorant as to...their s.h.i.+p's course, they touch the magnet with a needle. This then whirls round in a circle until, when its motion ceases, its point looks direct to the north."110 The date of Alexander's description, probably written in Paris, has been fixed at about 1190. At that early date the compa.s.s was by no means in universal use aboard s.h.i.+ps. The date of Alexander's description, probably written in Paris, has been fixed at about 1190. At that early date the compa.s.s was by no means in universal use aboard s.h.i.+ps.

The stern rudder, also long known in China, probably had an independent European provenance, either in Byzantium or, more probably, in the Baltic. At least in Europe, its adoption was apparently not motivated by the need for better steering apparatus, since the age-old steering oar still gave satisfactory service. However, the new, larger cog now rose so high in the water that it required an extremely long steering oar when heeled over, presenting serious problems for the steersman. The cog's straight sternpost offered a likely place to hang a rudder, manipulated at first by a tiller outside the hull, later through a square port cut in the stern. No marked improvement in steering was gained; a s.h.i.+p still depended on s.h.i.+fting sails to execute a radical change in direction.11 But the new device saved time and effort by reducing drift and holding the vessel on course. But the new device saved time and effort by reducing drift and holding the vessel on course.112 By the late twelfth century, the two-masted s.h.i.+p had made its appearance in the Mediterranean. Both Venetian and Genoese s.h.i.+pyards turned out two- and three-deckers with a pair of masts carrying lateen sails, their large cargo holds reducing freight rates and so stimulating commerce in bulk goods.113 Even with stern rudder and lateen rig, sailing in the Mediterranean presented problems. Prevailing winds and currents made outward voyages east and south from Italy much easier than the return. In 1183 Ibn Jubayr, an Arab of Spain, sailed on a Genoese s.h.i.+p from Ceuta, on the Strait of Gibraltar, to Alexandria in only thirty-one days, but the much shorter return voyage from Acre in Asia Minor to Messina, Sicily, took him fifty-one days. Even with stern rudder and lateen rig, sailing in the Mediterranean presented problems. Prevailing winds and currents made outward voyages east and south from Italy much easier than the return. In 1183 Ibn Jubayr, an Arab of Spain, sailed on a Genoese s.h.i.+p from Ceuta, on the Strait of Gibraltar, to Alexandria in only thirty-one days, but the much shorter return voyage from Acre in Asia Minor to Messina, Sicily, took him fifty-one days.114 Galleys were handicapped in heavy weather because of their low freeboard, provided to afford maximum leverage to the oarsmen: the more nearly parallel the oars were with the water, the greater the mechanical advantage.115 Under sail, the galley had an additional problem, being unable to heel over very far in tacking into the wind. Another twelfth-century traveler, Roger of Hoveden, wrote, "Galleys cannot, nor dare not, go by that route [open sea from Ma.r.s.eilles to Acre] since, if storms strike, they may be swamped with ease. And therefore they ought always to proceed close to the land." The danger, added to the need to rest the crew, generally dictated coastal routes for galleys, which could maneuver away from lee sh.o.r.es without difficulty. But open-water crossings gave the sailing s.h.i.+p a great advantage in carrying cargo, especially in the easterly and southerly directions. Under sail, the galley had an additional problem, being unable to heel over very far in tacking into the wind. Another twelfth-century traveler, Roger of Hoveden, wrote, "Galleys cannot, nor dare not, go by that route [open sea from Ma.r.s.eilles to Acre] since, if storms strike, they may be swamped with ease. And therefore they ought always to proceed close to the land." The danger, added to the need to rest the crew, generally dictated coastal routes for galleys, which could maneuver away from lee sh.o.r.es without difficulty. But open-water crossings gave the sailing s.h.i.+p a great advantage in carrying cargo, especially in the easterly and southerly directions.116 The Renaissance of the Twelfth Century The innovations of the central Middle Ages in agriculture, power sources, handicraft production, building construction, and transportation were accompanied by dramatic developments in the realm of pure science. "The tenth century, though on the surface a time of invasion, cruelty, barbarism, and chaos," writes Richard C. Dales, "is nevertheless the turning point in European intellectual history in general and the history of science in particular."117 One of the Middle Ages' most important creations, the medical school, was founded at Salerno in the eleventh century, when by no coincidence the earliest cultural contacts with Islam occurred. General higher education had its beginnings in the cathedral schools founded in the tenth through twelfth centuries in Paris, Chartres, Rheims, Orleans, Canterbury, and other cities. Emphasis varied. Partly because of the Church's need to determine the dates of its movable feasts, astronomy was a favored subject, notably at Rheims under the scholar-teacher Gerbert, later Pope Sylvester II (reigned 9991003).

Gerbert adopted the cosmology of Ptolemy as the most reasonable of those available and reintroduced two ancient but neglected devices for cla.s.sroom demonstration: the abacus or calculating board, a set of counters arranged in columns for performing arithmetic, and the armillary sphere, a representation of the cosmos by an a.s.sembly of b.a.l.l.s, rods, and bands. Gerbert may also have employed the astrolabe, known to have reached Christian Europe from Muslim Spain at about this time. The Arabs had improved the instrument, giving it what amounted to its final form, as a stereographically projected map of the heavens, with the stars and ecliptic marked on a skeletal plate (the rete) that rotated over another plate (the climate) giving local coordinates.

The cathedral schools' teaching was not for the clergy alone; by the twelfth century, some fathers enrolled sons to prepare them for careers in the law and other secular callings, including the growing governmental bureaucracies. The abacus, coming into wide practical use during the eleventh century, was introduced into the Norman-English exchequer in the twelfth.118 In the mid-twelfth century, the "precocious humanism" (Carl Stephenson)119 nurtured by Gerbert, his pupil Richer, and other scholars met and merged with another current, the growing importance of the professions of law and medicine, to create the first universities, at Paris and Bologna. From its beginnings, the University of Paris as well as its early offshoot, Oxford, articulated "productive ideas concerning nature as a fit subject of study." Scholars such as Peter Abelard (10791142) formulated "a new approach to the systematic study of science" (Tina Stiefel) even before the works of Aristotle became available in Latin. nurtured by Gerbert, his pupil Richer, and other scholars met and merged with another current, the growing importance of the professions of law and medicine, to create the first universities, at Paris and Bologna. From its beginnings, the University of Paris as well as its early offshoot, Oxford, articulated "productive ideas concerning nature as a fit subject of study." Scholars such as Peter Abelard (10791142) formulated "a new approach to the systematic study of science" (Tina Stiefel) even before the works of Aristotle became available in Latin.120 But it was the Muslim-a.s.sisted translation of Aristotle followed by those of Galen, Euclid, Ptolemy, and other Greek authorities and their integration into the university curriculum that created what historians have called "the scientific renaissance of the twelfth century." Certainly the completion of the double, sometimes triple translation (Greek into Arabic, Arabic into Latin, often with an intermediate Castilian Spanish vernacular) is one of the most fruitful scholarly enterprises ever undertaken. Two chief sources of the translations were Spain and Sicily, regions where Arab, European, and Jewish scholars freely mingled. In Spain the main center was Toledo, where Archbishop Raymond established a college specifically for making Arab knowledge available to Europe. Scholars flocked thither, headed by the prolific translator Gerard of Cremona, credited with seventy-eight works, several of them lengthy. To the Greek writings were eventually added many Arabic glosses and commentaries.

Some original Arabic works were also translated, such as the trigonometric tables of the mathematician al-Khwarizmi, given to the West by the enterprise of Adelard of Bath in 1126. By 1200 "virtually the entire scientific corpus of Aristotle" was available in Latin, along with works by other Greek and Arab authors on medicine, optics, catoptrics (mirror theory), geometry, astronomy, astrology, zoology, psychology, and mechanics.121 As the rival cosmic systems of Aristotle and Ptolemy came under scrutiny, their differences drew critical attention. From a medieval point of view, Aristotle's system made logical sense but was devoid of practical value, that is, in dating movable feasts. That of Ptolemy was based on hard-to-believe (and in fact incorrect) celestial mechanics but "saved the appearances," that is, accounted for the apparent movement of the planets.122 Both authorities confirmed two basic a.s.sumptions, one right and one wrong: that the earth was a sphere, a fact observable in an eclipse of the moon and in the apparent descent of a departing s.h.i.+p, and second, that it was the center of the universe. This was a pervasive a.s.sumption, congenial to psychology as well as religion, since it centered the universe on mankind. It accounted satisfactorily for the paths of all the heavenly bodies except five recalcitrant planets, for whose apparently eccentric orbits Ptolemy had invented an elaborate explanation. For some reason, while Ptolemy's ma.s.sive astronomical work, the Both authorities confirmed two basic a.s.sumptions, one right and one wrong: that the earth was a sphere, a fact observable in an eclipse of the moon and in the apparent descent of a departing s.h.i.+p, and second, that it was the center of the universe. This was a pervasive a.s.sumption, congenial to psychology as well as religion, since it centered the universe on mankind. It accounted satisfactorily for the paths of all the heavenly bodies except five recalcitrant planets, for whose apparently eccentric orbits Ptolemy had invented an elaborate explanation. For some reason, while Ptolemy's ma.s.sive astronomical work, the Almagest Almagest, was translated, his Geography Geography was overlooked by Europeans until the fifteenth century, despite its greater practical significance. Islam, on the other hand, knew it through Syriac translations and probably also in the original Greek text and based a number of important Arabic treatises on it. was overlooked by Europeans until the fifteenth century, despite its greater practical significance. Islam, on the other hand, knew it through Syriac translations and probably also in the original Greek text and based a number of important Arabic treatises on it.

A fuller picture of the earth's surface and its inhabitants gradually emerged in the tenth and eleventh centuries, when despite wars, piracy, and Crusades, peaceful travel increased. The Arab geographer al-Biruni (9731048) a.s.serted that "to obtain information concerning places of the earth has now become incomparably easier and safer."123 Much of the Arab geographical lore was imported to Europe by way of Sicily, whose Norman conquerors of the 1070s, inheriting and tolerating a population of Muslims, Jews, and Christians, maintained contacts with the Islamic world and showed a marked interest in scientific learning. At the command of King Roger II, a distinguished North African scholar, al-Idrisi (11001165), a.s.sembled an academy of geographers to collect and evaluate information on boundaries, climates, mountains, rivers, seas, roads, crops, buildings, crafts, culture, religion, and language, combining the study of previous geographical works (including Ptolemy's) with original research. Travelers were interviewed, the crews and pa.s.sengers of s.h.i.+ps docking in Sicily were interrogated, and expeditions, accompanied by draftsmen and cartographers, were dispatched to areas on which information was lacking. In a word, scientific method was applied to geographical research. Much of the Arab geographical lore was imported to Europe by way of Sicily, whose Norman conquerors of the 1070s, inheriting and tolerating a population of Muslims, Jews, and Christians, maintained contacts with the Islamic world and showed a marked interest in scientific learning. At the command of King Roger II, a distinguished North African scholar, al-Idrisi (11001165), a.s.sembled an academy of geographers to collect and evaluate information on boundaries, climates, mountains, rivers, seas, roads, crops, buildings, crafts, culture, religion, and language, combining the study of previous geographical works (including Ptolemy's) with original research. Travelers were interviewed, the crews and pa.s.sengers of s.h.i.+ps docking in Sicily were interrogated, and expeditions, accompanied by draftsmen and cartographers, were dispatched to areas on which information was lacking. In a word, scientific method was applied to geographical research.

The resulting compendium was called Nuzhat al-mushtag fi ikhtiraq al-afaq Nuzhat al-mushtag fi ikhtiraq al-afaq (The Delight of One Who Wishes to Traverse the Regions of the World), or, more simply, (The Delight of One Who Wishes to Traverse the Regions of the World), or, more simply, al-Kitab ar-Rujari al-Kitab ar-Rujari (Roger's Book). It contained a world map and seventy sectional itinerary maps representing the seven climates of the habitable world (according to Ptolemy), each divided longitudinally into ten sections, and a minute account of the regions thus ill.u.s.trated. To accompany it, Idrisi constructed a great silver disk almost eighty inches in diameter and weighing over 300 pounds, incised with the limits of the climates and outlines of countries, oceans, rivers, gulfs, peninsulas, and islands. Written in Arabic and never translated into Latin, (Roger's Book). It contained a world map and seventy sectional itinerary maps representing the seven climates of the habitable world (according to Ptolemy), each divided longitudinally into ten sections, and a minute account of the regions thus ill.u.s.trated. To accompany it, Idrisi constructed a great silver disk almost eighty inches in diameter and weighing over 300 pounds, incised with the limits of the climates and outlines of countries, oceans, rivers, gulfs, peninsulas, and islands. Written in Arabic and never translated into Latin, Roger's Book Roger's Book exerted little direct, but probably considerable indirect, influence on European thought through the mingling of Arabic scientific traditions with Norman and Italian maritime enterprise. exerted little direct, but probably considerable indirect, influence on European thought through the mingling of Arabic scientific traditions with Norman and Italian maritime enterprise.124 The twelfth century also witnessed the tardy introduction to Europe of the second of the great "false sciences," alchemy, whose sister, astrology, had remained known and practiced in unbroken continuation since Roman times. Once regarded as a pair of fruitless medieval exercises in superst.i.tion and charlatanism, the two have gained stature with the maturing of the history of science. An early recognition of alchemy's value was voiced by Francis Bacon (15611626), who recounted the story of "the man who told his sons that he had left them gold buried somewhere in his vineyard; where they by digging found no gold, but by turning the mould about the roots of the vines, procured a plentiful vintage. So the search and endeavors to make gold have brought many useful inventions and instructive experiments to light."125 The first Arabic treatise on alchemy to be translated into Latin was rendered by Robert of Chester in 1144, quickly followed by several more as the new science caught on.126 Alchemy had two aspects, theoretical and practical. The involved and mystical theorizing led nowhere, but the practice of alchemists in their laboratories became the direct ancestor of modern chemistry and chemical technology. Alchemy had two aspects, theoretical and practical. The involved and mystical theorizing led nowhere, but the practice of alchemists in their laboratories became the direct ancestor of modern chemistry and chemical technology.

Practicing alchemists pursued two aims: the conversion of base metals into gold, usually by means of the elusive "philosophers' stone," and the discovery of the "elixir of life" (also known as the "most active principle" or the "fountain of youth"), which would confer immortality. The first kind of research, based on the hypothesis that gold is the sole pure metal and that all the others are impure versions of it, led to acc.u.mulation of knowledge about physical and chemical reactions, while the second kind gradually turned into iatrochemistry, the search for healing drugs.

Medieval alchemists, Arabic and European, introduced no wholly new equipment into their laboratories, but they created a multiplicity of furnaces and stills. Furnaces of varying sizes were needed partly to accommodate the diversity of fuels-charcoal, peat, dried dung-and partly to provide the varied temperatures required for calcination (reduction of solids to powder) of different substances. Bellows were much employed, causing alchemists in France to be nicknamed souffleurs souffleurs (blowers). (blowers).127 A parallel collection of stills served the alchemists' other princ.i.p.al technique, distillation (boiling and condensation to separate compound substances). A parallel collection of stills served the alchemists' other princ.i.p.al technique, distillation (boiling and condensation to separate compound substances).128 The typical still was a tall vessel shaped like a church spire, mounted on a short tower; the fire in the lower part heated liquid whose steam condensed in the upper part and was guided by a long spout to another vessel. The typical still was a tall vessel shaped like a church spire, mounted on a short tower; the fire in the lower part heated liquid whose steam condensed in the upper part and was guided by a long spout to another vessel.129 Early stills lacked an efficient cooling device, and volatile liquids were usually lost. The still in which condensation was effected outside the still head may have been invented by a physician of Salerno named (for the city) Salernus (d. 1167). One product of the process, alcohol, strengthened by redistilling, found a variety of uses, as a solvent, a preservative, and the basis of brandy, gin, and whiskey, at first taken medicinally, later recreationally. Early stills lacked an efficient cooling device, and volatile liquids were usually lost. The still in which condensation was effected outside the still head may have been invented by a physician of Salerno named (for the city) Salernus (d. 1167). One product of the process, alcohol, strengthened by redistilling, found a variety of uses, as a solvent, a preservative, and the basis of brandy, gin, and whiskey, at first taken medicinally, later recreationally.

Both astrology and alchemy remained sources of interest to intellectuals long after the Middle Ages, but the importance of the magical element in medieval science has been exaggerated. "The striking thing about the [twelfth] century," in the words of Richard Dales, "is the att.i.tudes of its scientists...daring, original, inventive, skeptical of traditional authorities...determined to discover purely rational explanations of natural phenomena," in short, portending "a new age in the history of scientific thought."130 The healthy skepticism of the men of the twelfth-century renaissance was underpinned by a distinct, even enthusiastic naivete (Abelard and Heloise, his bluestocking mistress, named their son Astrolabe). Devout clergymen, they innocently conceived investigation of the natural world as their Christian duty, undertaken in a spirit of grat.i.tude toward G.o.d, "to help men reach a higher level of understanding of the Creator" (Tina Stiefel).131 So far from antic.i.p.ating conflict between study of natural phenomena and Church doctrine, they felt that their researches helped combat the ancient, still popular pagan superst.i.tions centered on magical trees, rocks, streams, and forests. So far from antic.i.p.ating conflict between study of natural phenomena and Church doctrine, they felt that their researches helped combat the ancient, still popular pagan superst.i.tions centered on magical trees, rocks, streams, and forests.132 In the demythologizing of nature, the medieval Church, following the lead of Boethius, antic.i.p.ated the Renaissance humanists. As George Ovitt observes, "The In the demythologizing of nature, the medieval Church, following the lead of Boethius, antic.i.p.ated the Renaissance humanists. As George Ovitt observes, "The scientia scientia of the Middle Ages was theology, but theology was understood to include not only the nature of G.o.d and of moral laws, but also the nature of the world created by G.o.d." of the Middle Ages was theology, but theology was understood to include not only the nature of G.o.d and of moral laws, but also the nature of the world created by G.o.d."133 EUROPE 1200.

Of all the changes in the appearance and activities of western Europe by the end of the twelfth century-castles and cathedrals, land clearance, swamp drainage, waterwheels and windmills, hospitals and universities-the most impressive lay in the realm of commerce. Many more pack trains and wagons were on the road; many more round s.h.i.+ps sailed northern and southern seas. Behind commerce, industry flourished, an industry that still fas.h.i.+oned articles one by one, by hand, but an industry vigorous, growing, and with potential for the future.

In the old-fas.h.i.+oned history books with their political maps, Europe of 1200 figured as an incoherent jumble of petty princ.i.p.alities and cloudy sovereignties, seeming to stand still or even move backward in respect to the modern world. But looking past popes, Holy Roman Emperors, counts, landgraves, and archbishops, and focusing on the worlds of agriculture, commerce, manufacture, and intellectual activity, one can discern a region economically coherent and intellectually dynamic, borrowing, adapting, inventing, and synthesizing technology.

6.

THE H HIGH M MIDDLE A AGES.

12001400 THE TWO CENTURIES THAT FOLLOWED THE period of European emergence are usually pictured in sharp contrast: the thirteenth, sometimes called the Golden Century, an era of affluence and growth, the fourteenth one of catastrophe and contraction. The contrast, however, has been overemphasized at the expense of important elements of continuity.

Throughout the thirteenth century, Europe's technological advances continued in all sectors, sustained, among other factors, by an era of mild climate favorable to crops.1 Communication between Europe and Asia benefited significantly from the conquests of the Mongols, whose ferocity in war contrasted with the peaceful character of the empire they imposed from Hungary to the Pacific Ocean. Papal amba.s.sador John of Pian de Carpine (1246), friar William of Rubruck serving as an envoy from King Louis IX of France (1253), and merchant Marco Polo (1260) were only the most famous of the Europeans who were now able to make the direct acquaintance of Chinese civilization and technology. One aim of the European visitors, however, Christian proselytizing, had little success among either Mongols or Chinese. Communication between Europe and Asia benefited significantly from the conquests of the Mongols, whose ferocity in war contrasted with the peaceful character of the empire they imposed from Hungary to the Pacific Ocean. Papal amba.s.sador John of Pian de Carpine (1246), friar William of Rubruck serving as an envoy from King Louis IX of France (1253), and merchant Marco Polo (1260) were only the most famous of the Europeans who were now able to make the direct acquaintance of Chinese civilization and technology. One aim of the European visitors, however, Christian proselytizing, had little success among either Mongols or Chinese.

In Europe, the Golden Century shone not only in Gothic architecture but in the rapid expansion of the Commercial Revolution. In its vanguard stood the cities of northern Italy, whose businessmen discovered (or borrowed) new machinery, new processes, and new business techniques. The fall of the Crusader states to Muslim reconquest had little effect on the predominantly Italian merchant colonies in the Levant ports, which continued to govern themselves and do business, now with the protection of the Islamic authorities. Europeans even moved into Egypt, where they had not previously ventured, to pick up the spices brought across the Indian Ocean by the Arabs, for which Alexandria was the chief entrepot.2 In the fourteenth century, the traffic s.h.i.+fted toward the territory of the friendly Mongol Empire, inspiring Europeans to think grandiose thoughts about gaining control of the whole spice trade. In 1318 a Dominican friar, William Adam, proposed stationing in the Red Sea a blockading squadron of galleys manned by Genoese, whom he esteemed as "the best and greediest of sailors," to shut the Arabs out of the spice trade altogether. In the fourteenth century, the traffic s.h.i.+fted toward the territory of the friendly Mongol Empire, inspiring Europeans to think grandiose thoughts about gaining control of the whole spice trade. In 1318 a Dominican friar, William Adam, proposed stationing in the Red Sea a blockading squadron of galleys manned by Genoese, whom he esteemed as "the best and greediest of sailors," to shut the Arabs out of the spice trade altogether.3 The scheme was not so much chimerical as premature, and in the meantime the Mongol Empire first turned hostile to European Christians and then collapsed, helping to deflect European attention toward the possibility of circ.u.mnavigating Africa. The scheme was not so much chimerical as premature, and in the meantime the Mongol Empire first turned hostile to European Christians and then collapsed, helping to deflect European attention toward the possibility of circ.u.mnavigating Africa.

The emerging Christian kingdoms of the Iberian peninsula, most strategically located for that enterprise, also turned to Genoa for s.h.i.+pbuilding and navigational help. Ugo Venta was the first of several Genoese admirals of Castile. Manuel Pessagno, appointed the first admiral of the Portuguese fleet in 1264, was succeeded by five generations of his family.4 Genoese expertise was part of a substantial input of European naval and military technology to the Reconquista, which among other things signaled a s.h.i.+ft in the pattern of technical diffusion between Christian and Islamic cultures: improvements in arms and armor were now copied by the Muslims from the Europeans. Genoese expertise was part of a substantial input of European naval and military technology to the Reconquista, which among other things signaled a s.h.i.+ft in the pattern of technical diffusion between Christian and Islamic cultures: improvements in arms and armor were now copied by the Muslims from the Europeans.5 Among its far-reaching effects, the accelerating Commercial Revolution provoked a demand for more coin metal, stimulating a historic development in central Europe: the opening of the rich silver-copper-gold mines in Bohemia, the Carpathians, and Transylvania, whither German miners from the Harz Mountains brought their skills. Underground mining developed rapidly, with the introduction of the vertical waterwheel for drainage, and the Chinese wheelbarrow.6 In northern Europe, the cities of the Hanseatic League not only successfully battled pirates but, accepting a challenge from the Danes, overthrew Danish hegemony and became the dominant power in the northern seas. Their larger s.h.i.+ps reduced freight rates, and they built lighthouses and quays, marked reefs and channels with buoys, trained pilots to navigate coastal waters, and composed their own maritime law.7 The disasters of the fourteenth century came in three shapes: first, the bankruptcies of several of the great Italian commercial and banking houses; second, a series of wars, especially the English-French Hundred Years War; and third, a succession of famine years (13151317), followed a generation later by the terrible visitation of the Black Death, which crept across Europe in 134849, abating only to return at intervals in this and the following century.

The source of the Black Death remains a mystery (a contemporary chronicler attributed it to the Mongol siege of Genoese-held Caffa, on the Black Sea, where corpses of plague victims were catapulted into the Genoese compound), and even the disease's ident.i.ty as bubonic plague has been questioned.8 What is certain is that a European population that was already declining was devastated. Families were extinguished, villages left deserted, cities depopulated. Yet the resilience with which Europe survived and recovered is as noteworthy as the calamity itself. Agriculture and commerce resumed, property was redistributed among survivors, and earlier marriage lifted the birthrate, beginning the restoration of the population. What is certain is that a European population that was already declining was devastated. Families were extinguished, villages left deserted, cities depopulated. Yet the resilience with which Europe survived and recovered is as noteworthy as the calamity itself. Agriculture and commerce resumed, property was redistributed among survivors, and earlier marriage lifted the birthrate, beginning the restoration of the population.9 In sum, the much-advertised disasters of the fourteenth century only temporarily disrupted economic life and had no discernible effect on technical progress, where the train of improvements continued in cloth making, construction, metallurgy, navigation, and other arts. On the political level, the century saw a s.h.i.+ft toward modern political organization, especially marked in England and France, as central monarchies acquired stronger instruments of power, better sources of revenue, and expanded administrative machinery.

Perhaps most significant, if least obtrusive, was the advance toward modern business methods and organization. "Unstinting credit was the great lubricant of the Commercial Revolution," according to Robert Lopez.10 The formation of large trading companies dealing extensively in credit transactions gave rise, first in Italy, then elsewhere, to commercial banking, dominated by such swiftly growing family-based inst.i.tutions as the House of Medici. To serve the more complex business world, new record-keeping devices, notably double-entry bookkeeping, were invented. The formation of large trading companies dealing extensively in credit transactions gave rise, first in Italy, then elsewhere, to commercial banking, dominated by such swiftly growing family-based inst.i.tutions as the House of Medici. To serve the more complex business world, new record-keeping devices, notably double-entry bookkeeping, were invented.

The Countryside: Estate Management and the Black Death The European countryside experienced the vicissitudes of the thirteenth and fourteenth centuries in the most marked degree. The thirteenth was a period of intensive cultivation, from which most of our information about medieval estate management derives; the fourteenth one of crop failures, plague, and agrarian disorders, and subsequent adjustments.

Thirteenth-century agriculture produced little new technology but a change in management methods and a substantial increase in production. Many lords had previously been content to "farm" their estates, that is, turn them over to outside entrepreneurs who paid a fixed yearly sum and collected rents, fines, and other proceeds. As the market grew with the population, opening the way to cash profits, the lords tended to a.s.sume direct control. Their tenants also benefited from prosperity and the money economy to buy their way free from many of the old manorial obligations. A few acquired land and even got modestly rich.

A sign of the lords' new interest in their agricultural affairs was the appearance of medieval Europe's first practical treatises on agronomy. Columella, Varro, and other Roman writers had long been read in the monasteries, and a few Arabic works from Spain had been translated, but the value of both Roman and Muslim authors was limited by their focus on Mediterranean-style farming methods, designed for conditions quite different from those