In c.610 in Mecca he received the first of a series of revelations which, as the Koran, became the doctrinal and legislative basis of Islam. In the face of opposition to his preaching he and his small group of supporters were forced to flee to Medina in 622 (the Hegira). Muhammad led his followers into a series of battles against the Meccans. In 630 Mecca capitulated, and by his death Muhammad had united most of Arabia.