The Abacus and the Cross: The Story of the Pope Who Brought the Light of Science to the Dark Ages
By Nancy Marie Brown
(Basic Books, 310 pp., $27.95)

A study of twenty member states of the Organization of the Islamic Conference (recently re-named the Organization of Islamic Cooperation, or OIC—the international body that represents Ummah al Islam, with a permanent delegation to the United Nations) found that between the years 1996 and 2003 those countries spent 0.34 percent of their GDP on scientific research, one-seventh of the global average. (Saudi Arabia and Indonesia invest a dismal 0.05 percent.) Those same twenty countries had an average of just ten scientists, engineers, or technicians per thousand citizens, the world average being forty, and that of the developed world—140. In a survey in 2008 of six Muslim countries—Egypt, Indonesia, Kazakhstan, Malaysia, Pakistan, and Turkey—a discouraging 85 percent rejected the notion that evolution is either “true” or “probably true.” In 2005, seventeen Muslim countries belonging to the OIC produced a total of 13,444 scientific publications, which for that year was 2,000 less than were published by Harvard researchers alone.

There are 1.6 billion Muslims in the world, and 60 percent of them are under thirty years old. Many of them are being taught, in madrassas and in universities, that important aspects of modern science clash with deep tenets of Islam. They are also being taught, in some cases, that there is such a thing as “Islamic science,” and that while the Koran prefigures momentous discoveries such as the Big Bang and quantum mechanics, much of Western science is inherently destructive, and cannot fulfill the needs of Muslim societies. Where there is no separation between church and state, and where the lack of a central church, as in Catholicism, has precluded an equivalent to the Protestant Reformation’s challenge to church authority, such trends are troublesome. There may be no “official” position on evolution or cloning or global warming, but religion has a powerful grip on all forms of intellectual inquiry. This has led to a surge of speculation and argumentation from scholars and critics about the very possibility of the growth of science in Muslim countries.

Whatever the claim, whatever the attitude, everyone agrees that in the world of Islam, science has fallen on tough times. But it was not always so. Following the death of the prophet Muhammad in 632 A.D., the period known as the High Caliphate ushered in the Golden Age of Islam, which would flourish well into the fourteenth century. With trade and commerce booming to the east with China, and back westward to North Africa and southern Europe, the wars that had separated diverse peoples and ethnic groups before the Arab conquests slowly began to quiet down. Gradually the cultural heritages of Persia, India, and Greece were assimilated into a growing Islamic civilization whose lingua franca became Arabic. And while the ulama, or Islamic scholars, continued to influence daily life by interpreting and redacting sharia law and Muslim theology, a polite, worldly culture of art, literature, poetry, and music came to mark the existence of the professional, courtly, and genteel classes. Increasingly, falsafa, Greek philosophy, was translated and taught by falasifa. And a new kind of scholar came into being, the hakim, or sage—polymaths sponsored by caliphs who took a leading role in transmitting and extending the science and wisdom of the ancient world throughout the growing empire.

Their achievements are legendary. There was the alchemist ibn Hayyan, who identified sulfuric and nitric acid and described reduction and distillation. There were the Banu Musa brothers, whose storied contributions to automation were described in their Book of Ingenious Devices. There was the Persian mathematician, geographer, and astronomer Musa al-Khwarizmi, who adopted the Indian numbering system (later known as Arabic numerals), developed algebra (derived from the title of his book Al-Kitab al-mukhtasar fi hisab al-jabr wa ’l-muqabalah, or The Compendious Book on Calculation by Completing and Balancing), and gave us the algorithm (derived from his name). There was al-Battani, the astronomer who accurately determined the length of the solar year, and Abu Bakr Zakariya al-Razi, who identified smallpox and measles, realized that fever was part of the body’s defenses, and wrote a twenty-three-volume compilation of Chinese, Indian, Persian, Syriac, and Greek medicine. There was ibn al-Haytham, the Egyptian astronomer and student of optics, who questioned Ptolemy’s celestial model and suggested the mathematics of refraction and reflection, and Omar Khayyam, famous for his poetry, but also the man who found geometric solutions to all thirteen forms of cubic equations, as well as developing a number of quadratic equations still in use today. There was the great Uzbeki physician, astronomer, and physicist Ibrahim ibn Sina, who composed The Canon of Medicine, and studied the different forms of energy as well as the properties of light. And there was Baghdad’s House of Wisdom, where the works of Euclid, Archimedes, Aristotle, Ptolemy, and Galen, as well as ancient manuscripts in Persian, Sanskrit, and Syriac, were translated and preserved. By the time of al-Khwarizmi’s death in 850, his and other science had reached Islamic Spain, where al-Hakam II built his Royal Library in Córdoba, just west of the Great Mosque. It was said, in 976, to house 400,000 books. The kingdom of al-Andalus, “of forests and fruit trees and rivers of sweet water,” as one Arab traveler wrote, was based on religious tolerance and scholarly inquiry: Arabic was the spoken tongue, but Christians wrote erotic poetry and sang Masses in it, and Jews flourished as politicians and intellectuals. And if the Royal Library really held a tenth of the books it was said to hold, a mere forty thousand, the monastery of Bobbio in Italy, the greatest Christian library of the time, held 690.


FIVE HUNDRED YEARS after the fall of the Roman Empire, Europe wallowed in obscurity. The grandsons of the great Charlemagne, King of the Franks and Emperor of the Romans, had since partitioned his kingdom between successive overlords, short-lived and weak of will. The ancient divide between free men and slaves was slowly giving way to a new kind of social trinity: churchmen, noblemen, and serfs. It would later be called feudalism, and it demolished the free peasant. Rich enough to own a horse and sword, a peasant could become a knight, and thus a nobleman, but most, becoming serfs, simply lost the right to bring a lawsuit to court, or to bear witness for a neighbor, or marry who they chose—not to mention losing their land, often bartered to a castellan in exchange for merciful protection. Purgatory would not be invented until the twelfth century, but the rough life called out for purification. And much of the business found itself on the doorstep of the monastery.

Here life was austere and virtually silent, a striking antithesis to the sensuous bustle of al-Andalus. Obeisant monks dressed in woolen tunics shuffled among their seven daily prayers, washing and eating in between. Following the Rule of Saint Benedict, speech was allowed only twice daily, in two short periods in the morning and evening, though conversation with God was continuous. Using the “language of the fingers and the eyes,” a monk would wipe his lips with a raised finger for “I don’t know,” lick his fingers for “honey,” and spread his fingers over his face and pull them away fast, like the claws of a bird, for “bad.” He would spend much time in solitude. At prayer he would become a surrogate for the sinners: alms-giving and monastery endowments gradually became tantamount to buying a monk’s prayers.

Increasingly, he would read books and produce them. For most, it was the only way to get an education: the monasteries, after all, were the only true schools. And so, while the Rule required monks to work, alongside shelling beans or rooting weeds or baking loaves of bread a conscript would often find himself under candlelight in the scriptorium. Here skins of sheep or goats—or for special books, calves or even rabbits—were fashioned into libraries: a Bible demanded 150 sheepskins, and a copy of the complete Virgil, fifty-eight. It was a small cottage industry, complete with sheep-raisers and butchers and ink-makers. Expert scribes could produce an average of forty strokes (five to six words) a minute, and rubricators would add chapter and section titles in color. There were also illustrators, and those who meticulously sewed the pages. The monks did their fair share of complaining: “It is excessive drudgery,” one of them wrote in the tenth century. “It crooks your back, dims your sight, twists your stomach and sides. Pray, then, you who read this book, pray for poor Ralph.” But books, like relics, made a monastery’s name.

Gradually, the wisdom of the Arabs began making its way into the monasteries, some of whose cathedral schools, after a time, became Europe’s first universities. How precisely this happened has been the subject of a great deal of scholarship, and there is still much that we do not know. But in her beautiful new book, Nancy Marie Brown provides an important piece of the puzzle. It is the story of Gerbert of Aurillac, a brilliant man who rose from humble beginnings to the greatest heights of medieval power, ending his life in Rome in 1003 as Pope Sylvester II. Gerbert’s life, as well as his death, paints a fascinating tale of science and religion, one that provides further perspective on the plight of Islamic science today.


WHERE AND WHEN Gerbert was born remains a mystery—it was probably in a cluster of low stone cottages in the small village of Belliac around the year 949. Whether he was the son of a pastor or a shepherd, he was noticed by the local abbot and summoned to the nearby monastery at Aurillac, where he quickly distinguished himself for being unusually bright. It was there that Gerbert gained his love of knowledge and books, a passion that sent him, upon finishing the trivium (grammar, rhetoric, and dialectic), to Catalonia to complete the quadrivium (arithmetic, geometry, astronomy, and music) just north of flourishing al-Andalus.

Gerbert probably first came across the abacus in Catalonia. It was a calculating instrument whose name derived from the Latin for “table,” and it introduced the place-value method still in use today. Infinitely more practical than using pebbles, or calculi, moved across a board and clumped together to figure sums, the abacus also trumped the “finger numbers” systems most monks used to reckon taxes and tithes. Brown quotes the Venerable Bede, Anglo-Saxon monk of Northumbria, explaining finger counting in the year 725:

When you say one, bend the left little finger and touch the middle line of the palm with it. When you say two, bend the third finger to the same place ... When you say four, raise the little finger ... When you say seven, touch the base of the palm with the little finger and hold up all the other fingers ... When you say nine, bend the shameless finger in the same way.

This system quickly became elaborate: for 90,000, for example, Bede wrote, “place the left hand on the small of the back, with the thumb pointing towards the genitals.” Clearly, a better system was needed, and with the abacus based on the Arabic numerals one through nine rather than awkward Roman numerals (say, MMMMMMMMMMXCIX to signify 10,099), the Andalusians, via al-Khwarizmi and the Indians, had found one.

In Catalonia, too, Gerbert undoubtedly came across the celestial sphere, a globe-shaped instrument on a handle that Ptolemy had described in the second century in a work that circulated in al-Andalus, but only in Arabic. Such spheres allowed one to calculate the length of daylight for any day in any place, the height of the sun and moon, the day of the year, and the time of day, which was important not only for religious rites and prayer, but also for commerce. And it was also in Catalonia, in all likelihood, that Gerbert encountered the most powerful instrument of all: the astrolabe, or “star-holder.” An Arabic astronomer claimed, in 960, that it had no fewer than 1,760 uses. A disc in the shape of a flattened orb deep enough to hold a number of plates called tympans, this elaborate inclinometer was often made of copper, silver, or even gold, and adorned with azimuth lines and ornate engravings. Crucial for finding the Qibla, or the direction of Mecca, and for calculating the times for prayers, the astrolabe also serviced astronomers, astrologers, navigators, surveyors, and businessmen. It was the medieval computer, nothing more or less.

And so when Gerbert came north in 970 after three years in Catalonia, he brought with him knowledge scarcely found in Christendom. It therefore did not take long before he was noticed by the pope, who recommended to Otto the Great, Holy Roman Emperor and King of Germany and Italy, to hire Gerbert, then twenty, to tutor his son and inheritor. When Otto II, now eighteen, married a Greek princess from Constantinople two years later, Gerbert was headhunted as schoolmaster at Reims, a job he would hold until 989, when politics and intrigue took him elsewhere.

It was at Reims, then the leading city in France, that he left his scientific mark on the age, a fact cleared of much obscurity by the discovery in 2001 of a student’s copy of Gerbert’s own abacus board. Here was the very first introduction of Arabic numerals into France. Finally the tithe and leap year could be calculated easily, not to mention the date of Easter. But there was more to it, at least for Gerbert. For here was also a way to glance into the very mind of God, who, as the Christian thinker Boethius explained centuries earlier, had “ordered all things by number, measure, and weight.” Not content to use numbers solely for the purposes of the Church’s computus, Gerbert sought to study and teach mathematics, geometry, and astronomy for their own sake.

Students flocked to him from across the Alps and throughout the Empire: thirteen future bishops or archbishops, six abbots of important monasteries, Henry II’s secretary, Otto III’s chancellor, the future King Robert the Pious of France, the future Pope Gregory VI, and hundreds and hundreds more. It would take time and gumption to assimilate all the new knowledge and techniques—the fact that to this day we state in words the numerical amount that we write on checks is a relic of just such conservative resistance—but the tide could not be stopped. “Gerbert gave the Latin world the numbers and the figures of the abacus,” says a medieval mathematical manuscript. Soon a good mathematician became known as an abaci doctor, or simply, in honor of the human bridge responsible for introducing such wisdom, a “gerbercist.”

What happened next is a tale of medieval intrigue, which Brown tells colorfully and well. I will say only—I don’t want to spoil the pleasures of the book—that the boy from Aurillac soon found himself embroiled in battles among kings and bishops, Carolingians and Capetians, Holy Roman Emperors, popes and anti-popes. Some were his patrons, some his enemies. Backed by Otto the Great’s grandson, Otto III, he finally became pope himself, just a year shy of the millennium.

Otto and Gerbert shared dreams of empire, as the name Gerbert chose as pope—Sylvester II, after Emperor Constantine’s pope Sylvester I—attests. It was a vision of power backed by science and religion, one calculated to bring back the glory days of the Holy Roman Empire. But Otto soon died of malaria at twenty-two, and with him all of Gerbert’s dreams. He had not had much time for science in the Vatican, but during his tenure Christianity triumphed over paganism, from Greenland to the Black Sea. The job description had hitherto been merely the bishop of a rather decrepit Rome; but after Gerbert, the pope became the leader of Christendom.


WERE THE "DARK AGES" really so dark after all? It is to Petrarch that we owe that infamous notion. The fourteenth-century humanist needed to fashion the awakening of the wisdom of classical antiquity, in which he took part, as a counterpoint to European backwardness following the dissolution of Rome. The Greeks and Romans may have lacked Christ but they had culture, and it was this secular light that the religious humanists sought to restore. Politics was also a factor: the Italian city-states sought to break free of the Holy Roman Empire, and so its cultural achievements—including the arduous copying in monasteries of the same ancient books the humanists were now supposedly, and heroically, “discovering”—had to be downplayed. Thus the entire period between the fall of the Romans in the fifth century and the start of Renaissance humanism in the fourteenth century—what Petrarch called “the sleep of forgetfulness”—was painted darkly and vilified. And when the fifteenth-century historians Leonardo Bruni and Flavio Biondo spoke of the third and “better age” into which the world was entering, the media tempestas, or Middle Ages, were born.

Later, during the Protestant Reformation, the Middle Ages became dark for a different reason. Now it was Catholic corruption, not cultural sterility, that was to blame: here was a move to restore not ancient wisdom but biblical Christianity. But the Roman Catholic Church fought back, and, thanks to Cardinal Baronius’s Annales Ecclesiastici in 1602, a book described by Acton as “the greatest history of the Church ever written,” the “dark ages” were shrunk and transformed. Now, the claim went, the “darkness” was rather a sign of the dearth of written records and books in the period between the end of the Carolingian Empire in 888 and the “little Renaissance” of the twelfth century. Ever since, via the Enlightenment and Romanticism, historians have battled over the meaning of the term “dark”: does it signify, somewhat neutrally, “obscure,” or, more damningly, “backward”?

Every generation interprets the past through its present, and so it was with Pope Sylvester II, otherwise known as Gerbertus of Aurillac. Following his untimely death in Rome in 1003, the vicissitudes of his reputation traced a winding path. From “a man of such great genius and admirable eloquence that his glory blazed over all of Gaul like a burning flame”—written in his time by a monk named Richer of Saint-Remy—to a skillful astronomer who “among those shining, shone exceedingly” and was elevated to the papacy “on account of his incomparable scientific knowledge,” Gerbert later became a wizard who had made a pact with the devil.

This diatribe was concocted by Cardinal Beno at the behest of Emperor Henry IV: Henry wanted to replace Gerbert’s successor, Gregory VII, with a more tractable pope, so Beno fashioned Gregory a pupil of a warlock. Had not Gerbert, after all, used magical tricks to tell the time by the stars and taught cryptic geometrical theorems of patent wizardry? Before long Gerbert’s years in Spain had turned into a “series of magical escapades with beautiful women, Saracen wizards, and secret codes hidden in the constellations.” He was said to have built a talking statue with a human visage that answered questions. He was said to have collapsed in the church called the Holy Cross of Jerusalem because the Devil had promised him that he would not die until he sang Mass in the city by that name. The wisdom of the abacus, Arabic numerals, experimental geometry, and the astrolabe no longer served to elevate his reputation: from the thirteenth century on, Gerbert became known as the Magician Pope.

The “Dark Legend of Gerbert” was a sign of the times, a mélange of disdain for Islam, superstition based on ignorance, and courtly intrigue. It was dispelled for a time in the late sixteenth century, when the “pact with the devil” was uncovered by one of Luther’s disciples as a Catholic harangue against a man of science who saw through medieval Church hypocrisy. Even Baronius, the Vatican librarian, writing just as Galileo was turning his telescope to the skies, now saw Gerbert for what he really was, a “learned man ... ahead of his time.” Backward millenarians may have expected a terrible Day of Judgment at the year 1000, but Gerbert entertained no such folly. After all, he was the Scientist Pope.

Still, the story stuck. Gerbert had bought “evil wisdom” from Jews and Moors, terrified the populace with visions of Armageddon, and blasphemed the Church with ideas of the world as a magical orb. In fact, as Brown shows, the legend became a template for those who wished to draw a dividing line between science and religion. It was this same cast of mind that led Washington Irving, in the 1820s, to propagate the myth of Columbus battling an ignorant Church. (In fact, the Council of Salamanca, using the same methods that Gerbert knew, had been much more scientifically sophisticated than the explorer about the size and shape of the globe.) It led the English astronomer and philosopher William Whewell, the man who coined the term “scientist,” as well as Andrew Dickson White, the founder of Cornell University, in his History of the Warfare of Science with Theology in Christendom, which appeared in 1896, to argue that all medieval Christians believed in a flat Earth. (They certainly did not.) Until this very day, it stokes the fires of those who would have it that science and religion are forever inimical to each other.

THIS BRINGS US back to Islam. Historians of science have long debated the meaning and the importance of the Golden Age of the Muslims. Some portray its achievement as primarily the preservation of ancient wisdoms, especially those of the Greeks, rather than a creative enterprise of its own. Others hold that a Muslim scientific revolution occurred during the Middle Ages, one that lay the foundation of experimental science upon which modern civilization was born. But apart from this, though always connected, scholars argue also about Muslim decline. Some, skirting the problem, suggest that the true story lies less in the cultural and intellectual fall of the Muslim world, but rather in the rise of capitalism and prosperity in the West. Others, addressing the question more directly, point to the slow adoption of the printing press by Muslim countries, the lack of growth of universities, the legacy of colonialism, and the unmet challenges of democracy.

But whatever the reasons, one looms above them all. This is the continued and sustained deference to religious authority. Whether or not independence from such authority was the primary cause of the Scientific Revolution in Europe, there is no denying its centrality. Science can grow and even flourish outside of democracies, just as it can within and alongside religion, but it can never live long without freedom. Advocating “Islamic science” will no more serve the furtherance of scientific inquiry than Lysenkoist “proletarian, materialist, practical” science did in the Soviet Union. In the end, this is knowledge’s true demand: that it be unfettered, unshackled, at liberty to lead wherever reason takes it.

After September 11, 2001, Brown tells us, the Mathematical Association of America reminded its readers in a newsletter that “as mathematicians, we are all children of Islam.” Presumably, the idea was to dispel the hysterical notion that all Muslims are terrorists. Gerbert’s school in Reims, the newsletter went on to explain, was proof that Islam had played “a crucial role” in the development of the West. Indeed, it had. Perhaps one day it will again—but that day will have to be preceded by political and cultural reform. May the Arab Spring, for this reason among many others, blossom like the yesteryear figs and oranges of al-Andalus.

Oren Harman is chair of the graduate program in science, technology, and society at Bar Ilan University, and the author, most recently, of The Price of Altruism: George Price and the Search for the Origins of Kindness (W.W. Norton). This article ran in the November 3, 2011, issue of the magazine.