Arab prophet and founder of Islam. He was born in Mecca, where c.610 he received the first of a series of revelations which, as the Koran, became the doctrinal and legislative basis of Islam. His sayings (the Hadith) and the accounts of his daily practice (the Sunna) constitute the other main sources of guidance for most Muslims.
In the face of opposition to his preaching he and his small group of supporters were forced to flee to Medina in 622; this flight, known as the Hegira), is of great significance in Islam, and the Islamic calendar (which is based on lunar months) is dated from ad 622 (= 1 ah). (See also Mahomet.)