Muhammad ibn ‘Abdullāh ( ; ; pronunciation; also spelled Mohammed or Muhammed) (ca. 570 Mecca/مَكَهْ – June 8, 632 Medina),Elizabeth Goldman (1995), p. 63 is the founder of the religion of Islam إِسْلامْ and is regarded by Muslims as a messenger and prophet of , the last and the greatest law-bearer in a series of prophets. Muslims consider him the restorer of the uncorrupted original monotheistic faith (islām) of Adam, Noah, Abraham, Moses, Jesus and other prophets.F. E. Peters (2003), p. 9. He was also active as a diplomat, merchant, philosopher, orator, legislator, reformer, military general, and, according to Muslim belief, an agent of divine action.

Born in 570 CE in the Arabian city of Mecca,Encyclopedia of World History (1998), p. 452 he was orphaned at a young age and brought up under the care of his uncle Abu Talib. He later worked mostly as a merchant, as well as a shepherd, and was first married by age 25. Discontented with life in Mecca, he retreated to a cave in the surrounding mountains for meditation and reflection. According to Islamic beliefs it was here, at age 40, in the month of Ramadan, where he received his first revelation from God. Three years after this event Muhammad started preaching these revelations publicly, proclaiming that "God is One", that complete "surrender" to Him (lit. islām) is the only way (dīn) acceptable to God, and that he himself was a prophet and messenger of God, in the same vein as other Islamic prophets.Esposito (1998), p. 12; (1999) p. 25; (2002) pp. 4–5Alford Welch, Muhammad, Encyclopedia of Islam

Muhammad gained few followers early on, and was met with hostility from some Meccan tribes; he and his followers were treated harshly. To escape persecution Muhammad and his followers migrated to Medina (then known as Yathrib) in the year 622 CE. This event, the Hijra, marks the beginning of the Islamic calendar. In Medina, Muhammad united the conflicting tribes, and after eight years of fighting with the Meccan tribes, his followers, who by then had grown to ten thousand, conquered Mecca. In 632, a few months after returning to Medina from his Farewell pilgrimage, Muhammad fell ill and died. By the time of his death, most of the Arabian Peninsula had converted to Islam; and he united the tribes of Arabia into a single Muslim religious polity.

The revelations (or Ayat, lit. "Signs of God")—which Muhammad reported receiving until his death—form the verses of the Qur'an, regarded by Muslims as the “Word of God” and around which the religion is based. Besides the Qur'an, Muhammad's life (sira) and traditions (sunnah) are also upheld by Muslims. They discuss Muhammad and other prophets of Islam with reverence, adding the phrase peace be upon him whenever their names are mentioned. While conceptions of Muhammad in medieval Christendom and premodern times were largely negative, appraisals in modern times have been far less so. Besides this, his life and deeds have been debated by followers and opponents over the centuries.