I'm sorry if you're watching this, Uma Thurman. Being part of the Ummah trumped all other ties, including tribal ties, which got Muhammad into some trouble and brings us, at last, back to history. So as Muhammad's following in Mecca grew, the Ummah aroused the suspicion of the most powerful tribe in Mecca, the Quraysh. And it didn't matter that Muhammad himself was born into the Quraysh tribe because he wouldn't shut up about how there was only one god, which was really bad news to the Quraysh tribe because they managed the pilgrimage trade in Mecca, and if all those gods were false, it would be a disaster economically. Although come to think of it, in the end, the Meccan pilgrimage business turned out just fine. So the Quraysh forced Muhammad and his followers out of Mecca in 622 CE, and they headed to Yathrab, also known as Medina. This journey, also known as the Hijrah, is so important that it marks year zero in the Islamic calendar.