In Medina, located in present-day Saudi Arabia, Muhammad, one of the most influential religious and political leaders in history, dies in the arms of Aisha, his third and favorite wife. Some scholars have identified the date as June 8, 632, but note that the exact date is not possible to verify. Born in Mecca of humble origins, Muhammad married a wealthy widow at 25 years old and lived the next 15 years as an unremarkable merchant. In 610, in a cave in Mount Hira north of Mecca, he had a vision in which he heard God, speaking through the angel Gabriel, command him to become the Arab prophet of the “true religion.” Thus began a lifetime of religious revelations, which he and others collected as the Qur’an. These revelations provided the foundation for the Islamic religion. Muhammad regarded himself as the last prophet of the Judaic-Christian tradition, and he adopted the theology of these older religions while introducing new doctrines. His inspired teachings also brought unity to the Bedouin tribesmen of Arabia, an event that had sweeping consequences for the rest of the world. By the summer of 622, Muhammad had gained a substantial number of converts in Mecca, leading the city’s authorities, who had a vested interest in preserving the city’s pagan religion, to plan his assassination. Muhammad fled to Medina, a city some 200 miles north of Mecca, where he was given a position of considerable political power. At Medina, he built a model theocratic state and administered a rapidly growing empire. In 629, Muhammad returned to Mecca as a conqueror. During the next two and a half years, numerous disparate Arab tribes converted to his religion. By his death on June 8, 632, he was the effective ruler of all southern Arabia, and his missionaries, or legates, were active in the Eastern Empire, Persia and Ethiopia. During the next century, vast conquests continued under Muhammad’s successors and allies, and the Muslim advance was not halted until the Battle of Tours in France in 732. By this time, the Muslim empire, among the largest the world had ever seen, stretched from India across the Middle East and North Africa, and up through Western Europe’s Iberian peninsula. The spread of Islam continued after the end of the Arab conquest, and many cultures in Africa and Asia voluntarily adopted the religion. Today, Islam is the world’s second-largest religion.