Islam is known as one of the fastest-expanding religions in history. They were tolerant, and offered many alternatives to the other religions of conquered lands. Mohamed once stated that another religion can either believe in Islam, or pay to keep his own religion. He would give the religions protection in exchange for obedience. Despite the belief of spiritual drive for conquest, some believe the expansion of Islam was due to the deep desire for a more modern life (Document 7); they were driven to settle in the fertile crescent in order to obtain these modern luxuries.