The House of Wisdom

by Jonathan Lyons

  The sustained effort of such a large team of geographers, mathematicians, and other scientists would have been impossible without the personal interest and support of al-Mamun, whose death in 833 coincided with the completion of the project. Individual Muslim scholars then developed and refined the disciplines of geography and cartography over the succeeding centuries. Such an evolution was in keeping with the Arabs’ fundamental view of scholarship, that it was a dynamic process in which succeeding generations built on the work of their forerunners and all were united in a single grand enterprise. In the case of geography, the next phase was dominated by detailed descriptions of peoples, cultures, and the environment.

  This increasingly popular endeavor saw sophisticated travel writers and ethnographers gradually replace the mathematical astronomers behind the Mamun map and similar research. Such works were in the same tradition as Usama ibn Munqidh’s Book of Contemplation, that entertaining and edifying account of the Christian newcomers to the Middle East. In addition to its literary appeal, this new human geography also met the growing demands of central state administrators for better information on the lands and peoples under their dominion. Notably, it exhibited the Arabs’ genius for exploring in great detail the foreign practices, beliefs, and lifestyles of the cultures they encountered across the empire and beyond. This genre, writes one of its leading practitioners, Muhammad ibn Ahmad al-Muqaddasi, “pleases the king as well as the beggar.”33

  This quip must not be allowed to obscure the seriousness of purpose behind al-Muqaddasi’s classic text, The Best Divisions for Knowledge of the Regions, completed in 985 and based on two decades of travel and exploration across the Muslim world. His work is particularly notable for its insistence on the primacy of material that he has collected personally; such an approach, al-Muqaddasi notes with a touch of self-pity, at times subjected him to severe privation and “cost lots of money.” It is only when he is physically unable to reach an area that interests him that he is forced to rely reluctantly on the reports of others, but only “men of intelligence, whom I knew to be neither careless nor confused.”34 Throughout, al-Muqaddasi deliberately invokes the legal tradition of the Muslim jurists, with their strict hierarchy of religious sources. In this system, the Koran is the supreme authority, followed by the sayings of the Prophet, the hadith. Next comes the consensus of the theologians, and finally the art of legal reasoning by analogy. However, al-Muqaddasi dismisses the use of analogies as completely unsuitable for the geographer’s art.35

  Such precision in identifying the source of information and the insistence, wherever possible, on personal observation and experience is a hallmark of medieval Arab science. It is also the invaluable legacy of Islam’s religious traditions, in which enormous efforts were devoted to preserving and assessing critically the chain of transmission for any recorded saying of Muhammad. Thus, each such statement is accompanied by a scholarly pedigree that spells out whether it is “strong” (that is, reasonably certain to reflect the Prophet’s words and intent) or “weak” (of dubious provenance and thus of little value for jurists and theologians). Al-Muqaddasi, too, puts an explicit premium on direct experience over hearsay: “This book of ours, then, falls into three parts: first, what I myself have witnessed; second, what I have heard from persons worthy of confidence; and third, what I have found in books devoted to this subject … No royal library remained without my persistent examination of it, no literary works of any sect that I have not scrutinized, no people with whose opinions I have not acquainted myself; there is no group of ascetics with which I did not mingle, no preachers anywhere whose convocations I have not attended. In this way, I attained to the soundness of knowledge I strove for in this science.”36

  Some time around 1138, the Arab scholar and fallen aristocrat al-Sharif al-Idrisi received one of the most remarkable invitations in the history of science. A widely traveled poet, pharmacologist, and botanist—his technical works give the names of plants in Arabic, Persian, Latin, Greek, Berber, and Sanskrit—al-Idrisi was offered a once-in-a-lifetime commission to oversee the production of a new world map, to be etched into a three-hundred-pound silver disk by royal engravers, and to write an accompanying text of descriptive geography.37 Only this time, the patron was neither caliph nor sultan, but the upstart Christian king of once-Muslim Sicily, Roger II.

  Roger’s Norman forebears arrived in Sicily, mostly as mercenaries in the service of local Christian and Muslim warlords, in the early eleventh century and decided to stay. They gradually increased their hold on the island and made significant inroads on the southern Italian mainland, then mostly inhabited by Greeks under Byzantine rule. When Roger reached the age of maturity, in 1112, he resolved to make the former Arab administrative center of Palermo his permanent capital. In a colorful description of the city three decades after Roger’s death, the travel writer Ibn Jubayr sets aside his bitterness at the Christian conquest just long enough to praise Palermo’s charms: “It is an ancient and elegant city, magnificent and gracious, and seductive to look upon. Proudly set between its open spaces and plains filled with gardens, with broad roads and avenues, built in the Cordoba style, entirely from cut stone … The king, to whom it is his world, has embellished it to perfection and taken it as the capital of his Frankish kingdom—may God destroy it.”38

  Ibn Jubayr, whose accidental visit was the result of a shipwreck on his way back to Muslim Spain after completing the hajj, found a city and a kingdom at the very meeting point of East and West. At a time when many of his contemporaries, including some close family members, were inflamed with the ideology of holy war, Roger II deliberately settled into his predominantly Muslim city, then home to more than three hundred mosques. He adopted Islam’s established approach to religious minorities, assessing a special poll tax on the Muslims and Jews but generally leaving them to manage their own affairs. He promulgated new laws that expressly recognized existing religious customs and traditions, organized the state bureaucracy along Arab lines, and promoted Muslim retainers to some of the state’s most powerful positions.39 Roger even entrusted important military units to his Arab subjects. The majority of the king’s foot soldiers and many of his horse archers were Muslims, a fact that scandalized the visiting archbishop of Canterbury.40 Arabs also comprised the bulk of the royal corps of engineers, responsible for the construction of fortifications, one of Roger’s keen interests, and for building and operating his fearsome mangonels and others engines of war.41

  Roger also patronized the island’s Arab artists, artisans, and craftsmen. A royal cloak created for the king around 1133 of the finest silk, now in a museum in Vienna, bears a distinctive Islamic design and an inscription in Arabic: “[This mantle] belongs to the articles worked in the royal treasury, in which fortune and honor, prosperity and perfection, merit, and distinction have their home.”42 Sicilian architecture under the Normans, including churches and chapels, features a compelling amalgam of mostly Arab and Eastern Christian design. Muslim poets were active at court, and the work of six survives in a twelfth-century Arabic compendium kept short by its editor so as not to offend religious sensibilities with its praise of the “infidel Nor-mans.”43 The only extant depiction of Roger, a mosaic in the Church of la Martorana in Palermo, shows the king with full black beard and mustache and dressed in Byzantine imperial robes with stylized Arabic Kufic script in the background.44 No wonder one prominent Arab chronicler reports that rumors swirled among the people that their king was really a secret Muslim, a reputation no doubt enhanced by Roger’s frequent clashes with the popes and his refusal to endorse the Crusades.

  Still, it is not clear how eager al-Idrisi was to settle in a Christian kingdom, albeit one as highly Arabized as Roger’s Sicily, and the circumstances surrounding his commission remain vague. The Arab chroniclers generally pay him scant attention in later life, perhaps a sign of disapproval over his association with the infidel king.45 At one point, Roger resorted to thinly veiled scare tactics, reminding the scholar that as a mem
ber of the former ruling Idrisid family he was at risk from the dynasty’s political enemies in Spain and North Africa. “You belong to the house of the caliphs,” Roger writes. “If you live among the Muslims, their rulers will contrive to kill you, but if you stay with me, you will be safe.”46 Alternatively, Roger may just have been showing off his considerable knowledge of Muslim history and internal politics in order to win al-Idrisi’s confidence.

  In any case, al-Idrisi accepted the king’s summons and soon settled in Palermo, where the pair began a fifteen-year collaboration that would produce one of the masterpieces of medieval geography. The great silver planisphere was stolen and melted down not long after its completion, but distinctive lapis hand-copied editions of al-Idrisi’s Map of the World survive, as do some partial sets of associated regional maps, ten for each of the seven traditional world climates. “So the total number of these sectional maps is seventy,” al-Idrisi tells us, “not counting the two extreme limits in two directions, one being the southern limit of human habitation caused by the excessive heat and lack of water and the other the northern limit of human habitation caused by excessive cold.”47

  Al-Idrisi and his team of researchers and scholars depicted the inhabited world as occupying one full hemisphere, or 180 degrees, stretching from Korea in the East to the Canary Islands in the West—the last confirmed lands before the inky black waters of the Atlantic, feared among the Arabs as the Sea of Darkness. Ten degrees on each side were allotted for the so-called Encircling Ocean that surrounds the earth’s landmass. Al-Idrisi drew on a wide range of sources, including the classics of Muslim geography and cartography, for knowledge of Africa and Asia. For information closer to home, he relied on his own career as a traveling scholar after his classical education in Cordoba, supplemented by the accounts of European travelers, merchants, diplomats, and members of Roger’s large navy.48 Al-Idrisi’s great geographic compendium, dated January 1154, is extant as well. By order of the king, the work was given the fanciful title Amusements for Those Who Long to Traverse the Horizon; understandably, the Arabs commonly referred to it simply as Kitab Rujar, or The Book of Roger.

  Al-Idrisi’s Book of Roger offered the medieval West the most comprehensive descriptions to date of the peoples, lands, and cultures of the seven climates. This was particularly the case for Africa, a region that generations of Arab sailors, traders, and adventurers knew well. Al-Idrisi provides detailed and generally accurate depictions of the gold trade of Ghana and the salt industry in the far west of the continent. He also describes the complex geography of the Upper Nile.49 Further to the east, The Book of Roger informs its readers of the practice of cannibalism on the island of Borneo, the intelligence of elephants, the caste system of India, and the Buddhist beliefs of the kings of far-off China.50 Gone is the traditional attention to details useful for efficient taxation, administration, trade, or conquest that characterized many earlier Arab works of descriptive geography. In their place is a full-fledged attempt to piece together the latest knowledge to create a coherent, comprehensive whole.51

  Al-Idrisi’s Map of the World was also important for the future of Western cartography and navigation, for it drew on the scientific traditions of Caliph al-Mamun and the researchers at the House of Wisdom and helped introduce them to a whole new audience. Western imitations of Arab maps began to appear by the late thirteenth century, including a work of cosmology by the Italian philosopher Brunetto Latini. The great German Scholastic Albertus Magnus also produced a basic world map around this time; it depicts Baghdad and the southern Iraqi city of Basra but not Paris and could only have been based on Muslim sources.52

  By their nature, maps are fragile and subject to the rigors of hard use. This is even more the case with navigational handbooks and coastal charts. In the days before printing, they were also difficult and costly to reproduce. So it is little wonder that not much has survived in the way of a “paper trail” directly linking specific advances in European maps and navigational charts to the earlier achievements of the Arab geographers and mariners. Still, a convincing picture of significant Muslim influence emerges from the scattered comments of Western sources as well as from an examination of the evolutionary course of early European cartography, particularly in the absence of contemporary European exposure to the distant Islamic world.

  One such clue lies in the marked improvement throughout the fourteenth century of European depictions of the Indian subcontinent, the Red Sea, the Persian Gulf, and Siberia, long known among Arab merchants as balad al-Sibir. These representations attained levels of precision unthinkable without reliable models to copy. European works also displayed accurate depictions of southern Asia and the eastern coast of Africa long before Western travelers had made their way to such remote regions.53 The Muslim understanding of Africa and the Indian Ocean was particularly important for the future of European exploration, for in overturning classical notions that the latter was landlocked, it showed that circumnavigation of southern Africa was not impossible.

  Another clue that early Christian cartographers were almost wholly reliant on foreign sources can be found in the curious history of mapping the Caspian Sea, actually the world’s largest lake. Fourteenth-century European maps, following the Muslim tradition, correctly captured the Caspian’s primary north-south orientation. By the early sixteenth century, however, Western geographers under the influence of recent Latin translations of much older works of Ptolemy had suddenly undone years of research by the Arabs and reverted to the classical representation of the Caspian as an oval running east to west. It would take another two centuries to repair the damage, eight hundred years after the Arabs had successfully charted the Caspian.54

  More important for the West than any specific borrowings from the Muslim geographers, however, was the general Arab intellectual legacy, conveyed in full by The Book of Roger, and its understanding of the world as a place that could be mapped, charted, and explored in a systematic and scientific fashion. World maps in the tradition of al-Mamun and al-Idrisi directly challenged the graphic representation of Christendom’s sacred geography, the flat-earth T-O maps with their stylized three continents, Europe, Asia, and Africa. At the same time, the Arab works of human geography presented the world as a place of marvels, diverse cultures, and varied peoples to be noted, cataloged, and studied, not shunned in favor of exclusive contemplation of eternal life in heaven.

  This Arab intellectual conception of the world was accompanied at times by some vital practical assistance. The Portuguese explorer Vasco da Gama, who had already completed his celebrated voyage around Africa’s southernmost point, the Cape of Good Hope, in 1497, was then guided to India by a Muslim map and, perhaps, even a Muslim pilot. According to a contemporary Portuguese account, da Gama and his officers were given a glimpse of a detailed map of the entire Indian coastline, “equipped with numerous meridians and parallels in the manner of the Moors.”55 Arab sources, acknowledging the calamity of allowing European powers to penetrate the Indian Ocean and its vital trade routes, all agree that the Muslim pilot must have been drunk at the time to commit such treachery against his fellow believers. Portuguese naval forces later captured invaluable maps of the eastern Spice Islands. These were rushed back to Lisbon for translation and incorporation into the Europeans’ increasingly accurate charts and atlases.

  Christopher Columbus also benefited from the work of the Arabs, particularly a Latin translation in the mid-twelfth century of the Sabean Tables, which summarized the latest techniques of Arab mathematical geography. In addition, Columbus and other explorers of his generation were influenced by recent Christian interpretations of classical Arab and Hindu notions of a symmetrical earth, a worldview that supported Columbus’s strategy of going east by sailing west. They may also have been encouraged by their mistaken reading of the Arabic sources, particularly accounts of the Abbasid determination of the length of one degree, which led them to believe the earth was 20 percent smaller than it really is.56 Finally, there are suggest
ions that Muslim seafarers—Arab, Malian, and Chinese—all made early voyages into the distant reaches of the Sea of Darkness, possibly extending as far as the New World.

  King Roger II was one of the first of a new breed of Europeans beginning to emerge from firsthand experience of the Arabs, not as enemies in holy war but as undisputed masters of science, philosophy, and high culture. He read Arabic and was widely familiar with the works of the leading Muslim scholars. Coins minted by Roger in 1138 are the earliest known in Europe to use the new Arabic numeral system popularized by al-Khwarizmi.57 His court physicians were all Arabs and, says the twelfth-century historian Ibn al-Athir, he relied on them more than on any Christian monk or priest at the palace.58 A Christian chronicler says the king above all else esteemed “honest and wise men, whether from his own land or born elsewhere, laymen or clerics.”59 So it was only natural that Roger would entrust his scientific lifework to a Muslim scholar.