Born Muhammad ibn Abdullah, he is said to have initially been a merchant who traveled widely.
Muhammad often retreated to the mountains outside Mecca, for prayer and contemplation. Muslims believe that in 610, at about the age of forty, while praying in one of these mountain caves called Hira, he was visited by the Angel Gabriel who commanded him to memorize and recite the verses sent by God. These verses were later collected as part of the Qur'an. Gabriel told him that God (Allah in Arabic) had chosen him as the last prophet to mankind. He eventually expanded his mission as a prophet, publicly preaching a strict monotheism and warning against a Day of Judgement where all humans shall be held responsible for their deeds. He did not completely reject Judaism and Christianity, two other monotheistic faiths known to the Arabs; rather he said that he had been sent by God in order to complete and perfect their teachings.
By the time of Mohammad's death, he had unified Arabia, spread Islam throughout the Arabian Peninsula