From the Holy Qur'an: Chapters 53, 84-93, Part 1 of 2

Prophet Muhammad, Peace Be Upon Him, was born in 570 AD in Mecca, in what is now known as Saudi Arabia. At about age 40, he retired to a cave in the mountains and engaged in deep meditation. During this period of inner introspection, he first received messages from Allah through the Archangel Gabriel. The record of these divine relations, which spanned over 23 years, can be found in the most holy book of Islam - the Qur’an.