the islamic prophet, muhammad, was born in mecca in about 571. from the early 7th century, muhammad united the various tribes of the peninsula and created a single islamic religious polity. following his death in 632, his followers rapidly expanded the territory under muslim rule beyond arabia, conquering huge swathes of territory. although arabia soon became a politically peripheral region as the focus shifted to the more developed conquered lands, mecca and medina remained the spiritually most important places in the muslim world. the qur'an requires every able-bodied muslim who can afford it, as one of the five pillars of islam, to make a pilgrimage, or hajj, to mecca during the islamic month of dhu al-hijjah at least once in his or her lifetime.