1. He was born an orphan.
His father died without knowing he had a son, and Muhammad was farmed out to Beduin foster parents for the first five years of his life, returning to his mother in Mecca for only a year until she also died. The 6-year-old was left on the margins -- an outsider within his own society. He was put to work as a camel boy on the trade caravans to Damascus, and though he eventually made his way up to become a business agent, could never take his place in the world for granted.
2. He married up -- and for love.
The widowed Khadija was 40, he was 25, and since she was his employer, it was she who proposed to him. Some scholars have assumed that the "wealthy widow" syndrome was at work here, but early accounts indicate a marriage of mutual love and respect -- a monogamous one that lasted 24 years until her death. He'd mourn her until his own death 13 years later.
His nine late-life marriages were mainly means of diplomatic alliance and of securing his base, as was customary for any leader of the time. It's striking that though he'd had five children with Khadija (four daughters, and a son who died in infancy), he'd have none with any of the later wives.
3. His first reaction to becoming a prophet? Doubt and despair.
He was terrified by the first Quranic revelation, which happened on a mountain just outside Mecca in the year 610, when he was 40. In his own reported words, the pain was so intense that he thought he was dying. Convinced that he was either delusional or possessed, since it seemed impossible that someone like him could be a prophet, his first impulse when he found himself still alive was to try to finish the job himself and leap off the mountain to his death.
4. He led an early form of Occupy Wall Street.
His message constituted a radical protest against the corruption and arrogance of the Meccan elite. As both a pilgrimage and trading hub, the city had combined piety and profit to become a kind of seventh-century bull market. Muhammad's ongoing revelations demanded social and economic justice, and this provoked intense opposition from the city's rulers (as did his outrage at the preference for sons over daughters and the ensuing practice of female infanticide). The intent was reform, but those in power saw it as a subversive call for revolution.
5. He was a pacifist -- at first.
For 12 years, he took a proto-Gandhian stance of passive resistance to organized harassment of him and his small group of followers in Mecca -- "these nobodies" as his opponents called them. The Quranic revelations constantly urged him to "reply to foolish mockery with words of peace," to "pay no attention," and to "turn your face away" -- words one sometimes wishes more of his followers heeded today. When the assaults became physical as well as verbal, he refused to fight back or to allow his followers to do so. In the year 622, the attacks culminated in a concerted attempt on his life, forcing him into exile in Medina, 200 miles to the north.
His eventual decision to take up arms in exile was highly ambivalent - the result of political pressure as he assumed political as well as spiritual leadership. In fact the first of the three battles he'd lead against Mecca began as much by miscalculation as by intent. Yet even after his home city accepted his leadership in a negotiated surrender and welcomed him back -- the outsider transformed within eight years into the ultimate insider -- he'd never return to live there, but would stay in Medina.
6. He knew how to say he was wrong.
He acknowledged his own fallibility, most notably in the now infamous case of "the Satanic verses," when he tried to mend the rift between himself and his opponents by acknowledging their totem gods as intercessors with the one supreme god. When he realized that he'd been tempted into betraying his principles and that there could be "no partners with God," he had the courage and integrity to publicly declare his mistake.
7. His tragic failure came at the end.
He died without designating a successor. In the absence of a son, many thought it crucial that he make his wishes unequivocally clear, but though his final illness lasted 10 days (the duration and symptoms seem to indicate bacterial meningitis), he never did so. Ironically, the prophet of unity -- one god, one people -- thus paved the way for the divisiveness between Sunni and Shiite that persists today.