Islam's Empire

Islam was born in Arabia in the early 7th century, when Muhammad ("the Prophet") began experiencing visions that he believed came from God. Within a few generations, Muhammad's followers had built one of the biggest empires in human history: the caliphate. Here's how.

From Arabia Out

Even when Muhammad was alive, Islam was a religion with a strong political component. The goal was to spread the faith to new regions, and the method was often conquest. When possible, Muhammad used diplomatic means to unify Arabia. But when he came up against groups hostile to his religious reformation, he dealt with them at the point of a sword. He was good at it, too. By the time he died in 632, he had unified most of Arabia and reached as far north as Syria.

When Muhammad died, the community he left behind accepted that it was to continue the expansion the Prophet had begun. First, though, they had to choose a new leader, or "caliph" (Arabic khalifah, "successor"). So a group of Muslim elders gathered at Medina and selected Abu Bakr, Muhammad's father-in-law, to take charge.

The first four caliphs--Abu Bakr, Umar, Uthman, and Ali--all held power at a time when Islam's armies marched freely across the Middle East and mounted preliminary raids into North Africa, Armenia, and Persia. But choosing successors proved complicated.

From Muhammad to Ali

When the second caliph, Umar, died, many expected Ali to get the nod. After all, Ali was Muhammad's son-in-law and, by some indications, the Prophet's hand-picked successor. But the elders appointed Uthman, a member of the wealthy Umayyad clan.

In 656, Uthman was murdered by an angry mob, and his grisly end fractured the young Muslim community. The prominent families of Medina chose Ali as caliph, while the Umayyad families designated their own man. Ali was forced to flee to Iraq, where he was assassinated in 661. He was buried in Najaf, which soon became a holy site.

In the years to come, members of the Muslim community in Iraq, known as Shi'ites (Arabic shi'at Ali, "party of Ali"), chose spiritual leaders (Arabic imams) who were descended from Ali--the only line of descent they recognized. Meanwhile, the Umayyads continued to rule the rest of the caliphate.

From Africa to India

Umayyad armies conquered North Africa and most of Spain in the early 8th century and pushed as far east as India's Indus River valley. Soon, Islam's empire ranked among the largest in history. At the same time, it had probably grown too large. The Franks stopped a Muslim invasion cold in 732. Then, in 750, a major rebellion by the Abbasid family destroyed the Umayyad dynasty.

The Abbasids moved the capital to Baghdad and enjoyed stable rule for a century. Still, pieces of the empire began to fall away. Finally, in 945, Baghdad fell to tribesmen from northwestern Iran. The Abbasid caliphs stayed on as figureheads, and they did manage to maintain some spiritual authority. But rival caliphs were proclaimed in Tunisia and Spain, and the centralized political authority once personified by the caliph was shattered forever.