THE ORIGINS AND SPREAD OF ISLAM

A Vision, a Text

In the early life of Muhammad, little suggested that momentous events would soon occur. Born in Mecca around 570 CE into a well-respected tribal family, he enjoyed only limited financial success as a trader. Then came a revelation, which would convert this merchant into a proselytizer of a new faith. In 610 CE, while the forty-year-old Muhammad was on a monthlong spiritual retreat in a cave near Mecca, he believed that God came to him in a vision and commanded him to recite these words:

Recite in the Name of the Lord who createth,

Createth man from a clot

Recite: And thy Lord is the most Bounteous who teacheth by the pen

Teacheth man that which he knew not.

Further revelations followed. The early ones were like the first: short, powerful, emphasizing a single, all-powerful God (Allah), and full of instructions for Muhammad’s fellow Meccans to carry this message to nonbelievers. The words were eminently memorable, an important feature in an oral culture where poetry recitation was the highest art form. Muhammad’s early preaching had a clear message. He urged his small band of followers to act righteously, to set aside false deities, to submit themselves to the one and only true God, and to care for the less fortunate—for the Day of Judgment was imminent. Muhammad’s most insistent message was the oneness of God, a belief that has remained central to the Islamic faith ever since.

These teachings, compiled into an authoritative version after the Prophet’s death, constituted the foundational text of Islam: the Quran. Its 114 chapters, known as suras, occur in descending order of length; the longest has 300 verses and the shortest, a mere 3. Accepted as the very word of God, they were believed to flow without flaw through God’s perfect instrument, the Prophet Muhammad. Muhammad believed that he was a prophet in the tradition of Moses, other Hebrew prophets, and Jesus and that he communicated with the same God that they did. The Quran and Muhammad proclaimed the tenets of a new faith intended to unite a people and to expand the faith’s spiritual frontiers. Islam’s message already had universalizing elements, though how far it was to be extended, whether just to the tribal peoples living in the Arabian Peninsula or well beyond, was not at all clear at first.

The Move to Medina

In 622 CE, Muhammad and a small group of followers, opposed by Mecca’s leaders because of their radical religious tenets and their challenge to the ruling elite’s authority, escaped to Medina. Known as the hijra (“breaking off of relations” or “departure”), the perilous 200-mile journey yielded a new form of communal unity: the umma (“band of the faithful”). So significant was this moment that Muslims date the beginning of the Muslim era from this year.

Medina became the birthplace of a new faith called Islam (“submission”—in this case, to the will of God) and a new community called Muslims (“those who submit”). The city of Medina had been facing tribal and religious tensions, and by inviting Muhammad and his followers to take up residence there, its elders hoped that his leadership and charisma would bring peace and unity to their city. Early in his stay, Muhammad drew on the pragmatic business mindset he no doubt had acquired from years of working as a merchant to put forth the Constitution of Medina. This document laid down rules intended to promote harmony among the different groups in the city (including its Muslim and Jewish inhabitants), in part by requiring the community’s people to refer all unresolvable disputes to God and Muhammad. Now the residents were expected to replace traditional family, clan, tribal, and religious affiliations with loyalty to Muhammad as the one and true Prophet of God.

Over time, the core practices and beliefs of every Muslim would crystallize as the five pillars of Islam. Muslims were expected to (1) proclaim the phrase “there is no God but God and Muhammad is His Prophet”; (2) pray five times daily facing Mecca; (3) fast from sunup until sundown during the month of Ramadan; (4) travel on a pilgrimage (or hajj) to Mecca at least once in a lifetime if their personal resources permitted; and (5) pay alms in the form of taxation that would alleviate the hardships of the poor. These clear-cut expectations gave the imperial system that would soon develop a doctrinal and legal structure and a broad appeal to diverse populations.

Muhammad’s Successors and the Expanding Dar al-Islam

In 632 CE, in his early sixties, the Prophet passed away; but Islam remained vibrant thanks to the energy of the early followers—especially Muhammad’s first four successors, the “rightly guided caliphs.” The Arabic word khalīfa means “successor,” and in this context it referred to Muhammad’s successors as political rulers over Muslim peoples and the expanding state. Their goal was to institutionalize the new faith. They set the new religion on the pathway to imperial greatness and linked religious uprightness with territorial expansion, empire building, and an appeal to all peoples. (See Current Trends in World History: The Origins of Islam in the Late Antique Period: A Historiographical Breakthrough.)

Driven by religious fervor and a desire to acquire the wealth of conquered territories, Muslim soldiers embarked on military conquests and sought to found a far-reaching territorial empire. This expansion of the Islamic state was one aspect of the struggle that they called jihad. From the outset, Muslim religious and political leaders divided the world into two units: the dar al-Islam (or the world of Islam) and the dar al-harb (the world of warfare). Within fifteen years, Muslim soldiers had grasped Syria, Egypt, and Iraq—centerpieces of the former Byzantine and Sasanian Empires that now became pillars undergirding an even larger Islamic empire. Mastery of desert warfare and inspired military leadership yielded these astonishing exploits, as did the exhaustion of the Byzantine and Sasanian Empires after generations of warfare.

The Byzantines saved the core of their empire by pulling back to the highlands of Anatolia, where they had readily defensible frontiers. In contrast, the Sasanians gambled all, hurling their remaining military resources against the Muslim armies, only to be crushed. Having lost Iraq and unable to defend the Iranian plateau, the Sasanian Empire passed out of existence.

Creating an empire and stabilizing it were two different things. A political vacuum opened in the new and growing Islamic empire with the assassination of Ali, the last of the “rightly guided caliphs.” Ali, an early convert to Islam, was a fierce leader in the early battles for expansion. The Umayyads, a branch of the Quraysh (a powerful tribe in Mecca), laid claim to Ali’s legacy. Having been governors of the province of Syria under Ali, this first dynasty moved the core of Islam out of Arabia to the Syrian city of Damascus. They also introduced a hereditary monarchy, the Umayyad caliphate, in 661 CE to resolve leadership disputes. Although tolerant of conquered populations, Umayyad dynasts did not permit non-Arabic-speaking converts to hold high political offices, an exclusive policy that contributed to their ultimate demise.

Difficulties in Documentation

Little can be gleaned about Muhammad and the evolution of Islam from Arabic-Muslim sources known to have been written in the seventh century CE. Non-Muslim sources, especially Christian and Jewish texts, which are often unsympathetic to Muhammad and early Islam, are more abundant and contain useful data on the Prophet and the early messages of Islam. These non-Muslim sources raise questions about Muhammad’s birthplace, his relationship to the most powerful of the clans during his stay in Mecca, and even the date of his death. Many of these sources, as well as the Quran itself, stress the end-times content of Muhammad’s preaching and the actions of his followers. The conclusion that scholars derive from these sources is that it was only during the eighth century CE, in the middle of the Umayyad period, that Islam lost its end-of-the-world emphasis and settled into a long-term religious and political system.

The only Muslim source that we have on Muhammad and early Islam is the Quran itself, which, according to Muslim tradition, was compiled during the caliphate of Uthman (r. 644–656 CE). Recent scholarship has questioned this claim, suggesting a later date, sometime in the early eighth century CE, for the standardization of the Quran. Some scholars even contend that the text by then had additions to, and redactions of, Muhammad’s message. The Quran, in fact, is quiet on some of the most important events of Muhammad’s life. It mentions the name of Muhammad only four times. For more information, scholars have depended on biographies of Muhammad, one of the first of which was compiled by Ibn Ishaq (704–767 CE); this work is not available to present scholars, but it was used by later Muslim authorities, notably Ibn Hisham (d. 833 CE), who wrote The Life of Muhammad, and Islam’s most illustrious early historian, Muhammad Ibn al-Jarir al-Tabari (838–923 CE). Although the works of these later writers come from the ninth and tenth centuries CE, Muslim tradition ever since has held these sources to be reliable on Muhammad’s life and the evolution of Islam after the death of the Prophet.

The Abbasid Revolution

As the Umayyads spread Islam beyond Arabia, some peoples resisted what they experienced as Arab Umayyad religious impurity and repression. In particular, they believed that their continuing discrimination despite their conversion to Islam was humiliating and unfair. The Arab Umayyad conquerors enslaved large numbers of non-Arabs in the course of their conquests. These enslaved peoples could lose their servile status only through manumission. Even so, the non-Arab freed people who converted found that they, too, were still regarded as lesser persons although they lived in Arab households and had become Muslims. This situation existed even though the Arabs totaled about 250,000 to 300,000 during the Umayyad era, while non-Arab populations were 100 times as populous, totaling between 25 and 30 million. The area where protest against Arab domination reached a crescendo was in the east, notably in Khurasan, which included portions of modern-day Iran, Turkmenistan, Uzbekistan, Tajikistan, and Afghanistan. In Khurasan, most of the Arab conquerors did not live separately from the local populations in garrison cities (as was commonplace elsewhere) but were in close contact and intermarried local, ethnically different women. One of the early leaders of the protest movements in Khurasan was Abu Muslim, whose message about Islam was that it was a universal religion, open equally to all groups. He did not claim that he traced his heritage through one group over another, but instead asserted that he descended from Islam.

Even though opponents assassinated Abu Muslim, they did not silence his message. A coalition of dissidents emerged under a movement that harkened back to Abbas Ibn Abd al-Muttalib (568–653 CE), an uncle of the Prophet. This Abbasid movement, named for Muhammad’s uncle, thus claimed descent from the Prophet. Soon disgruntled provincial authorities and their military allies, as well as non-Arab converts, joined the Abbasids. After amassing a sizable military force, they trounced the Umayyad ruler in 750 CE. Thereafter, the center of the caliphate shifted to Iraq (at Baghdad; recall the opening anecdote about al-Mansur), signifying the eastward sprawl of the faith and its empire. This seismic shift also represented a success for non-Arab groups within Islam without eliminating Arab influence at the dynasty’s center—the capital, Baghdad, in Arabic-speaking Iraq. This process changed the nature of the emerging empire. For as the political center of Islam moved out of Arabia to Syria (at Damascus) and then with the Abbasids to Baghdad, ethnic and geographical diversity replaced what had been ethnic purity. Thus, even as the universalizing religion strove to create a common spiritual world, it became more diverse within its political dimensions.

Not only did the Abbasids open Islam to Persian peoples, but they also embraced Greek and Hellenistic learning, Indian science, and Chinese innovations. In this fashion, Islam, drawing its original impetus from the teachings and actions of a prophetic figure, followed the trajectory of Christianity and Buddhism and became a faith with a universalizing message and appeal. It owed much of its success to its ability to merge the contributions of vastly different geographical and intellectual territories into a rich yet unified culture. (See Map 9.1.)

THE GLOBAL VIEW

THE CALIPHATE An early challenge for the Abbasid rulers was to determine how traditional, or “Arab,” they could be and still rule so vast an empire. They chose to keep the bedrock political institution of the early Islamic state—the caliphate (the line of political leaders reaching back to Muhammad). Although the caliphs exercised political and spiritual authority over the Muslim community, they were not understood to have inherited Muhammad’s prophetic powers. Nor were they authorities in religious doctrine. That power was reserved for religious scholars, called ulama.

Abbasid rule borrowed practices from successful predecessors in its mixture of Persian absolute authority and the royal seclusion of the Byzantine emperors who lived in palaces far removed from their subjects. This blend of absolute authority and decentralized power involved a delicate and ultimately unsustainable balancing act. As the empire expanded, it became increasingly decentralized politically, enabling wily regional governors and competing caliphates in Spain and Egypt to grab power. Even as Islam’s political center diffused, though, its spiritual center remained fixed in Mecca, where many of the faithful gathered to circle the Kaaba and to reaffirm their devotion to Islam as part of their pilgrimage obligation.

THE ARMY The Abbasids, like all rulers, relied on force to integrate their empire. Yet they struggled with what the nature of that military force should be: a citizen-conscript, all-Arab force or a professional, even non-Arab, army. In the early stages, leaders had conscripted military forces from local Arab populations, creating citizen armies. But as Arab populations settled down in garrison cities, the Abbasid rulers turned to professional soldiers from the empire’s peripheries. Now they recruited from Turkish-speaking communities in central Asia and from the non-Arab, Berber-speaking peoples of North and West Africa. Their reliance on foreign—that is, non-Arab—military personnel represented a major shift in the Islamic world. Not only did the change infuse the empire with dynamic new populations, but soon these groups gained political authority. Having begun as an Arab state and then incorporated strong Persian influence, the Islamic empire now embraced Turkish elements from the pastoral belts of central Asia.

ISLAMIC LAW (THE SHARIA) AND THEOLOGY Islamic law began to take shape in the Abbasid period. The work of generations of religious scholars, sharia covers all aspects of practical and spiritual life, providing legal principles for marriage contracts, trade regulations, and religious prescriptions such as prayer, pilgrimage rites, and ritual fasting. As Islam spread to new regions, sharia responded to regional differences on all these issues. Sharia, in its regional diversity, has remained vital throughout the Muslim world, independent of empires, to the present day.

Early Muslim communities prepared the ground for the sharia, endeavoring (guided by the Quran) to handle legal matters in ways that they thought Muhammad would have wanted. The most influential early legal scholar was an eighth-century CE Palestinian-born Arab, al-Shafi’i, who wanted to make the empire’s laws entirely Islamic. He insisted that Muhammad’s laws as laid out in the Quran, in addition to his sayings and actions as written in later reports (hadith), provided all the legal guidance that Islamic judges needed.

The triumph of scholars such as al-Shafi’i was deeply significant: it placed the ulama, the Muslim scholars, at the heart of Islam. Ulama, not princes and kings, became the lawmakers, insisting that the caliphs could not define religious law. Only the scholarly class could interpret the Quran and determine which hadith were authentic. The ulama’s ascendance opened a sharp division within Islam: between the secular realm of the caliphs and the religious sphere of judges, experts on Islamic jurisprudence, teachers, and holy men.

GENDER IN EARLY ISLAM Pre-Islamic Arabia was one of the last regions in Southwest Asia where patriarchy had not triumphed. Instead, men still married into women’s families and moved to those families’ locations, as was common in tribal communities. Some women engaged in a variety of occupations and even, if they became wealthy, married more than one husband. But contact with the rest of Southwest Asia, where men’s power over women prevailed, was already altering women’s status in the Arabian Peninsula before the birth of Muhammad.

Muhammad’s relations with women reflected these changes. As a young man, he married a woman fifteen years his senior—Khadija, an independent trader—and took no other wives before she died. It was Khadija to whom he went in fear following his first revelations. She wrapped him in a blanket and assured him of his sanity. She was also his first convert. Later in life, however, he took younger wives, some of whom were widows of his companions, and insisted on their veiling (partly as a sign of their modesty and privacy). He married his favorite wife, Aisha, when she was only nine or ten years old. An important figure in early Islam, she was the daughter of Abu Bakr, who became the first caliph after Muhammad’s death. She became a major source for collecting Muhammad’s sayings.

By the time Islam reached Southwest Asia and North Africa, where strict gender rules and women’s subordinate status were entrenched, the new faith was adopting a patriarchal outlook. Muslim men could divorce freely; women could not. A man could take four wives and numerous concubines; a woman could have only one husband. Well-to-do women, always veiled, lived secluded from male society. Still, the Quran did offer women some protections. Men had to treat each wife with respect if they took more than one. Women could inherit property (although only half of what a man inherited). Marriage dowries went directly to the bride rather than to her guardian, indicating women’s independent legal standing. And while a woman’s adultery drew harsh punishment, its proof required eyewitness testimony. The result was a legal system that reinforced men’s dominance over women but empowered magistrates to oversee the definition of male honor and proper behavior.

Al-Khayzurān Bint Atta (d. 789) provides a fascinating exception to this rule. She exerted power during the reign of her husband, Abbasid caliph al-Mahdi (r. 775–785), and during the reign of her two sons. The historical tradition is somewhat hostile to her, depicting her as manipulative and overly domineering in her rise from total enslavement to umm walad (unsellable mother of her enslaver’s child), to wife, and then to mother of caliphs. Her reported ruthlessness even included maneuvering her younger son, Harun al-Rashid (r. 786–809), into power by having her elder son murdered. (For more on al-Rashid’s wealth, see Analyzing Global Developments: Islam and the Silk Trade: Adapting Religion to Opulence.) Al-Khayzurān’s reputed influence over al-Rashid is perhaps matched by that of Zubaidah (d. 831), the woman he married. Zubaidah was a well-educated woman, who went on pilgrimage multiple times and even donated money for the construction of several wells along the hajj route between Baghdad and Mecca. Either al-Khayzurān or Zubaidah, or a blend of both, may well have been the inspiration for the learned Scheherazade, whose stories to a jilted king compose One Thousand and One Nights. Together they demonstrate how extraordinary women could assert power even within a community becoming ever more patriarchal in outlook.

The Blossoming of Abbasid Culture

The arts flourished during the Abbasid period, a blossoming that left its imprint throughout society. Within a century, Arabic had superseded Greek as the Muslim world’s preferred language for poetry, literature, medicine, science, and philosophy. Like Greek, it spread beyond native speakers to become the language of the educated classes.

Arabic scholarship now made significant contributions, including the preservation and extension of Greek and Roman thought and the transmission of Greek and Latin treatises to Europe. Scholars in Baghdad translated the principal works of Aristotle; essays by Plato’s followers; works by Hippocrates, Ptolemy, and Archimedes; and the medical treatises of Galen, using these works to extend their understanding of the natural world. To house such manuscripts, patrons of the arts and sciences—including the caliphs—opened magnificent libraries.

The Muslim world absorbed scientific breakthroughs from China and other areas, incorporated the use of paper from China, adopted siege warfare from China and Byzantium, and applied knowledge of plants from the ancient Greeks. From Indian sources, scholars borrowed a numbering system based on the concept of zero and units of ten—what we today call Arabic numerals. Arab mathematicians were pioneers in arithmetic, geometry, and algebra, and they expanded the frontiers of plane and spherical trigonometry. Since much of Greek science had been lost in the west and later was reintroduced via the Muslim world, the Islamic contribution to the west was of immense significance. Thus, this intense borrowing, translating, storing, adding to, and diffusing of written works brought worlds together.

Islam in a Wider World

As Islam spread and became decentralized, it generated dazzling and often competitive dynasties in Spain, North Africa, and points farther east. Each dynastic state revealed the Muslim talent for achieving high levels of artistry far from its heartland. As more peoples came under the roof provided by the Quran, they invigorated a broad world of Islamic learning and science. But growing diversity led to a problem: Islam’s political structures could not hold its widely dispersed believers under a single regime. Although its political system shared many legal elements (especially those controlled by Islamic texts and its enforcers), in terms of secular power Islam was deeply divided. No single political regime could hold its widely dispersed believers together. (See Map 9.2.)

CITIES IN SPAIN One extraordinary Muslim state arose in Spain under Abd al-Rahman III (r. 912–961 CE), the successor ruler of a Muslim kingdom founded there over a century earlier. Abd al-Rahman III brought peace and stability to a violent frontier region where civil conflict had disrupted commerce and intellectual exchange. His evenhanded governance promoted amicable relations among Muslims, Christians, and Jews, and his diplomatic relations with Christian potentates as far away as France, Germany, and Scandinavia generated prosperity across western Europe and North Africa.

Abd al-Rahman III expanded and beautified the capital city of Cordoba, and his successors made the Great Mosque of Cordoba one of Spain’s most stunning sites. The Great Mosque of Cordoba, known in Spanish as la Mezquita, is the oldest standing Muslim building on the Iberian Peninsula. Begun in 785 CE by Abd al-Rahman I, it is a stirring tribute to the architectural brilliance and religious zeal of Iberia’s Muslims. Built in the form of a perfect square, its most striking features were alternating red and white arches, made of jasper, onyx, marble, and granite and fashioned from materials from the Roman temple and other buildings in the vicinity. These huge double arches hoisted the ceiling to 40 feet and filled the interior with light and cooling breezes. Around the doors and across the walls, Arabic calligraphy proclaimed Muhammad’s message and asserted the superiority of Arabic as God’s chosen language. In the nearby city of Madinat al-Zahra, Abd al-Rahman III surrounded the city’s administrative offices and mosque with verdant gardens of lush tropical and semitropical plants, tranquil pools, fountains that spouted cooling waters, and sturdy aqueducts that carried potable water to the city’s inhabitants.

CENTRAL ASIAN TALENT The other end of the Islamic empire, 8,000 miles east of Spain, enjoyed an equally spectacular cultural flowering. In a territory where Greek culture had once sparkled and where Sogdians had become leading intellectuals, Islam was now the dominant faith and the source of intellectual ferment.

The Abbasid rulers in Baghdad delighted in surrounding themselves with learned men from this region. They promoted and collected Arabic translations of Persian, Greek, and Sanskrit manuscripts, and they encouraged central Asian scholars to enhance their learning by moving to Baghdad. One of their protégés, the Islamic cleric al-Bukhari (d. 870 CE), was Islam’s most dedicated collector of hadith, which provided vital knowledge about the Prophet’s life.

Others made notable contributions to science and mathematics. Al-Khwarizmi (c. 780–850 CE) modified Indian digits into Arabic numerals and wrote the first book on algebra. The renowned Abbasid philosopher al-Farabi (d. 950 CE), from a Turkish military family, also made his way to Baghdad, where he studied eastern Christian teachings. Although he considered himself a Muslim, he thought good societies would succeed only if their rulers implemented political tenets espoused in Plato’s Republic. He championed a virtuous “first chief” to rule over an Islamic commonwealth in the same way that Plato had favored a philosopher-king.

In the eleventh century, the Abbasid caliphate began to decline, devastated by climatic change (see Chapter 10) and weakened from overextension and the influx of outsider groups (the same problems the Roman Empire had faced). Scholars no longer trekked to the court at Baghdad. Yet the region’s intellectual vitality remained strong, for young men of learning found patrons among local rulers. Consider Ibn Sina, known in the west as Avicenna (980–1037 CE). He grew to adulthood in Bukhara, practiced medicine in the courts of various Islamic rulers, and spent his later life in central Persia. Schooled in the Quran, Arabic secular literature, philosophy, geometry, and Indian and Euclidean mathematics, Ibn Sina was a master of many disciplines. His Canon of Medicine stood as the standard medical text in both Southwest Asia and Europe for centuries.

TRADE AND ISLAM IN SUB-SAHARAN AFRICA Carried by traders and scholars, Islam also crossed the Sahara Desert and penetrated well into Africa (see Map 9.3); there merchants exchanged weapons and textiles for gold, salt, and enslaved peoples. Trade did more than join West Africa to North Africa. It also generated prodigious wealth, which allowed centralized political kingdoms to develop. The most celebrated was Ghana, which lay at the terminus of North Africa’s major trading routes.

Seafaring Muslim traders carried Islam into East Africa via the Indian Ocean. There is evidence of a small eighth-century CE Islamic trading community at Lamu, along the northern coast of present-day Kenya; and by the mid-ninth century CE, other coastal trading communities had sprung up. They all exported ivory and, possibly, enslaved peoples. On the island of Pate, off the coast of Kenya, the inhabitants of Shanga constructed the region’s first mosque. This simple structure was replaced 200 years later by a mosque capable of holding all adult members of the community when they gathered for Friday prayers. By the tenth century CE, the East African coast featured a mixed African-Arab culture. The region’s evolving Bantu language absorbed Arabic words and before long gained a new name, Swahili (derived from the Arabic plural of the word meaning “coast”). In sub-Saharan Africa, as in North Africa and Asia, Islam promoted trade and elevated the status of merchants, who were themselves important agents for spreading their faith.

GREEN REVOLUTION IN THE ISLAMIC WORLD New crops, especially food crops, leaped across political and cultural borders during this period, offering expanding populations more diverse and nutritious diets and the ability to feed increased numbers. Most of these crops originated in Southeast Asia, made their way to India, and dispersed throughout the Muslim world and into China. They included new strains of rice, taro, sour oranges, lemons, limes, and most likely coconut palm trees, sugarcane, bananas, plantains, and mangoes. Sorghum and possibly cotton and watermelons arrived from Africa.

Once Muslims conquered the Sindh in northern India in 711 CE, the crop innovations pioneered in Southeast Asia made their way to the west. Soon a “green revolution” in crops and diet swept through the Muslim world. Sorghum supplanted millet and the other grains of antiquity because it was hardier, had higher yields, and required a shorter growing season. Citrus trees added flavor to the diet and provided refreshing drinks during the summer heat. Increased cotton cultivation led to a greater demand for textiles.

For over 300 years, farmers from northwest India to Spain, Morocco, and West Africa made impressive use of the new crops. They increased agricultural output, slashed fallow periods, and grew as many as three crops on lands that formerly had yielded one. (See Map 9.4.) As a result, farmers could feed larger communities; even as cities grew, the countryside became more densely populated and even more productive.

Opposition within Islam: Shiism and the Rise of the Fatimids

Islam’s whirlwind rise generated internal tensions from the start. It is hardly surprising that a religion that extolled territorial conquests and created a large empire in its first decades would also spawn dissident religious movements that challenged the existing imperial structures. Muslims shared a reverence for a basic text and a single God, but often they had little else in common. Religious and political divisions only grew deeper as Islam spread into new corners of Afro-Eurasia. Once the charismatic Prophet died, believers disagreed over who should take his place and how to preserve authority. Strains associated with selecting the first four caliphs after Muhammad’s death left a legacy of protest; to this day, they represent the greatest challenge facing Islam’s efforts to create a unified culture.

SUNNIS AND SHIITES The most powerful opposition movement arose in North Africa, lower Iraq, and the Iranian plateau. The questions that fueled disagreements were who should succeed the Prophet, how the succession should take place, and who should lead Islam’s expansion into the wider world. The vast majority of Muslims today are Sunnis (from the Arabic word meaning “tradition”). They accept that the political succession to the Prophet through the four rightly guided caliphs and then to the Umayyad and Abbasid dynasties was the correct one. Dissidents, such as the Shiites, contest this version.

Shiites (“members of the party of Ali”), among the earliest dissidents, felt that the proper successors should have been Ali, who had married the Prophet’s daughter Fatima, and his descendants. Ali was one of the early converts to Islam and one of the band of Meccans who had migrated with the Prophet to Medina. The fourth of the rightly guided caliphs, he ruled over the Muslim community from 656 to 661 CE, dying at the hands of an assassin who struck him down as he was praying in a mosque in Kufa, Iraq. Shiites believe that Ali’s descendants, whom they call imams, have religious and prophetic power as well as political authority—and thus should enjoy spiritual primacy.

Shiism appealed to groups whom the Umayyads and Abbasids had excluded from power; it became Islam’s most potent dissident force and created a permanent divide within Islam. Shiism was well established in the first century of Islam’s existence. Over time the Sunnis and Shiites diverged even more than the early political disputes would have indicated. Both groups had their own versions of the sharia, their own collections of hadith, and their own theological tenets.

FATIMIDS After 300 years of struggling, the Shiites finally seized power. Repressed in Iraq and Iran, Shiite activists made their way to North Africa, where they joined with dissident Berber groups to topple several rulers. In 909 CE, a Shiite religious and military leader, Abu Abdallah, overthrew the Sunni ruler there. Thus began the Fatimid regime.

After conquering Egypt in 969 CE, the Fatimids set themselves against the Abbasid caliphs of Baghdad, refusing to acknowledge their legitimacy and claiming to speak for the whole Islamic world. The Fatimid rulers established their capital in a new city that arose alongside al-Fustat, the old Umayyad capital. They called this place al-Qahira (or Cairo), “the Victorious,” and promoted its beauty. Early on they founded a place of worship and learning, al-Azhar Mosque, which attracted scholars from all over Afro-Eurasia and spread Islamic learning outward; they also built other elegant mosques and centers of learning. The Fatimid regime lasted until the late twelfth century, though its rulers made little headway in persuading the Egyptian population to embrace their Shiite beliefs. Most of the population remained Sunnis.

By 1000 CE, Islam, which had originated as a radical religious revolt in a small corner of the Arabian Peninsula, had grown into a vast political and religious empire. It had become the dominant political and cultural force in the middle regions of Afro-Eurasia. Like its rival in this part of the world, Christianity, it aspired to universality. But unlike Christianity, it was linked from its outset to political power. Muhammad and his early followers created an empire to facilitate the expansion of their faith, while their Christian counterparts inherited an empire when Constantine embraced their faith. A vision of a world under the jurisdiction of Muslim caliphs, adhering to the dictates of the sharia, drove Muslim armies, merchants, and scholars to territories thousands of miles away from Mecca and Medina. Yet the impulse to expand ran out of energy at the fringes of Islam’s reach, creating political fragmentation within the Muslim world and leaving much of western Europe and China untouched. But it also had important internal consequences: Muslims were no longer the minority within their own lands, owing to the conversion of Christians, Jews, and other populations under Muslim emperors.