Muslim history began in Arabia with the Muhammad's first recitations of the Qur'an in the 7th century. Islam's historical development has affected political, economic, and military trends both inside and outside the Islamic world. As with Christendom, the concept of an Islamic world is useful in looking at different periods of human history; similarly useful is an understanding of the identification with a quasi-political community of believers, or ummah, on the part of Islam's practitioners down the centuries.