This journey, also known as the Hijrah, is so important that it marks year zero in the Islamic calendar. In Medina, Muhammad severed the religion's ties to Judaism, turning the focus of prayer away from Jerusalem to Mecca. Also in Medina, the Islamic community started to look a lot more like a small empire than like a church. Like, Jesus never had a country to run, but Muhammad did almost from the beginning, and in addition to being an important prophet, he was a good general. And in 630, the Islamic community took back Mecca. They destroyed all those idols in the Kaaba, and soon Islam was as powerful a political force in the region as it was a religious one. And it's because the political and religious coexisted from the beginning that there's no separate tradition of civic and religious law like there is in Christianity and Judaism.