Muhammad (ca. 570–632 CE) (Arabic محمد) also transliterated Mohammad, Mohammed, Muhammed, and sometimes Mahomet (Latin Mahometus), following the Latin or Turkish), is believed by mainstream Muslims to be God's final prophet sent to guide mankind with the message of Islam. He is referred to as "The Prophet" (in Arabic النبي) within the faith. Non-Muslims generally consider him to be the founder of Islam.
According to traditional Muslim biographers, he was born ca. 570 in Mecca (Makkah) and passed away June 8, 632 in Medina (Madinah). Both Mecca and Medina are cities in the Hejaz region of present day Saudi Arabia. The name Muhammad means "the praised one" in Arabic.
Born Muhammad ibn Abdullah, he is said to have been a merchant who traveled widely. Muslims believe that in 610, at about the age of forty, while praying in a cave called Hira near Mecca, he was visited by the Angel Gabriel.
Later, he described the experience (to those close to him), and that the angel had commanded him to memorize and recite the verses sent by God which were later collected as part of the Qur'an. Gabriel told him that God (Allah in Arabic) had chosen him as the last of the prophets 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. Many of his neighbors resented his preaching, and persecuted Muhammad and his followers. In 622, he was forced to flee from Mecca and settled in Yathrib (now known as Medina) with his followers, where he was the leader of the first avowedly Muslim community. War between factions in Mecca and Medina followed, in which Muhammad and his followers were eventually victorious.
The military organization honed in this struggle was then set to conquering the other tribes of Arabia. By the time of Muhammad's death, he had unified Arabia, spread Islam throughout the Arab Peninsula, and launched expeditions to the north, towards Syria and Palestine.
Under Muhammad's immediate successors, the Islamic empire expanded into Palestine, Syria, Mesopotamia, Persia, Egypt, North Africa, and Iberia. Later conquests, commercial contact between Muslims and non-Muslims, and missionary activity spread Islam over much of the globe.
The sources available about Muhammad's life are the Qur'an, the sira biographies, and the hadith collections. While the Qur'an is not a biography of Muhammad, it does provide some information about his life. The earliest surviving biographies are the Life of the Apostle of God, by Ibn Ishaq (d. 768), edited by Ibn Hisham (d. 833); and al-Waqidi's (d. 822) biography of Muhammad. Ibn Ishaq wrote his biography some 120 to 130 years after Muhammad's death. The third source, the hadith collections, like the Qur'an, are not a biography per se. In both the Sunni and Shia belief, they are the accounts of the verbal and physical traditions of Muhammad.
Some skeptical scholars (Wansbrough, Cook, Crone, and others) have raised doubts about the reliability of these sources, especially the hadith collections. They argue that by the time the oral traditions were being collected, the Muslim community had fractured into rival sects and schools of thought. Each sect and school had its own sometimes conflicting traditions of what Muhammad and his companions had done and said.
Traditions multiplied, and Muslim scholars made a strenuous effort to weed out what they felt were spurious stories.
Traditionalists rely on their efforts while the skeptics feel that the question must be revisited.