The era of Mesopotamia that began with the fall of the Sassanian Empire and the introduction of Islam into the region in the seventh century a. d., in a sense marking the transition from ancient to medieval Mesopotamia. The last Sassanian king, Yazdgird III (reigned 633-651), was an ineffective ruler, and during his reign the empire declined and fell partially into a feudal state. This left it vulnerable to attack by some opportunistic group. That group turned out to be the Muslims, who had recently risen to power to the south of Mesopotamia in Arabia.
The origins of Islam in Arabia began with the birth of a boy called al-Amin (“the Faithful”), a member of the Quraysh tribe, in about 571. His parents died when he was young, and he was raised by his grandfather and a slave woman. As a young man, al-Amin became a merchant. But soon he grew dissatisfied with his life and received a vision of the angel Gabriel. The latter’s words to the young man became the basis of the Koran, the Muslim holy book, and the new faith of Islam. After being persecuted in Mecca in western Arabia, al-Amin traveled to Jerusalem and then to Medina, north of Mecca, where he adopted the name Muhammad and gained many converts. Islam soon spread to Mecca and other parts of Arabia.
Following Muhammad’s death in 632, his successors began a series of campaigns to spread their faith and political control over neighboring regions. In 634 an Arab Muslim army led by Khalid Ibn al-Walid invaded the Sassanian Empire. Two years later the capital of Ctesiphon was taken, and by 651 all of Mesopotamia, Iran, Syria, and Palestine were in Muslim hands. The Arabic language replaced Persian, and Islam became the official religion. Ten years later the first Muslim dynasty—the Umayyad—assumed power and its members ruled from 661 to 750. The Muslim era that followed them is referred to as the Abbasid Caliphate (750-1258), which ended with the invasion of Mesopotamia by the Mongols, a warlike people from central Asia.
See Also: Mesopotamia, history of; Sassa-nian Empire