"Muhammad was born approximately 570 CE (Year of the Elephant) in Mecca. He was the son of Abdullah ibn Abd al-Muttalib and Amina bint Wahb. His father was the son of Quraysh tribal leader Abd al-Muttalib ibn Hashim, and Abdullah died a few months before Muhammad's birth. His mother Amina died when he was six, leaving Muhammad an orphan.[6] He was raised under the care of his grandfather, Abd al-Muttalib, and paternal uncle, Abu Talib.[7] In later years, he would periodically seclude himself in a mountain cave named Hira for several nights of prayer. When he was 40, Muhammad reported being visited by Gabriel in the cave[8][9] and receiving his first revelation from God. In 613,[10] Muhammad started preaching these revelations publicly,[11] proclaiming that "God is One", that complete "submission" (islām) to God[12] is the right way of life (dīn),[13] and that he was a prophet and messenger of God, similar to the other prophets in Islam.[14][15][16]
Muhammad's followers were initially few in number, and experienced hostility from Meccan polytheists for 13 years. To escape ongoing persecution, he sent some of his followers to Abyssinia in 615, before he and his followers migrated from Mecca to Medina (then known as Yathrib) later in 622. This event, the Hijra, marks the beginning of the Islamic calendar, also known as the Hijri Calendar. In Medina, Muhammad united the tribes under the Constitution of Medina. In December 629, after eight years of intermittent fighting with Meccan tribes, Muhammad gathered an army of 10,000 Muslim converts and marched on the city of Mecca. The conquest went largely uncontested and Muhammad seized the city with little bloodshed. In 632, a few months after returning from the Farewell Pilgrimage, he fell ill and died. By the time of his death, most of the Arabian Peninsula had converted to Islam.[17][18]
The revelations (each known as Ayah – literally, "Sign [of God]") that Muhammad reported receiving until his death form the verses of the Quran, regarded by Muslims as the verbatim "Word of God" on which the religion is based. Besides the Quran, Muhammad's teachings and practices (sunnah), found in the Hadith and sira (biography) literature, are also upheld and used as sources of Islamic law (see Sharia)