It is told that the Archangel Gabriel appeared to Muhammad in a cave outside Mecca and commanded him to "Read!" three times. Each time Muhammad said that he cannot read (see Qur'an 96:1-5). This event happened around 610 A.D., and marks the period until his death in 632 A.D. in which he received various revelations from Allah. Muhammad taught these to his followers and many commited them to memory; some did so exhaustively. These revelations started to be written down sometime after Muhammad's death: most agree that this was in the 650s between 650 and 656 AD.
Muhammad and his follwers withdrew from Mecca to Medina in 622 A.D. after severe persecution. This hegira - or withdrawal - is used as the initial date of the Muslim era, Annus Hegirae, abbreviate A.H.
The first of the Five Pillars of Islam, the Shahadah, consists of sincere recitation of the creed:
- "There is no God but Allah and Muhammad is his messenger."