City to which Muhammed and early followers emigrated (hijrah) in 622 when persecuted by Meccans-and important due to Muhammed's grave being situated here. Originally known as Yathrib, it changed its name to "City of the Prophet" (madinat al-nabi). It became the place where Muhammed set the course for Islam to develop into a religious and political society; first he regulated the political problems of Medina by gaining assent to the Constitution of Medina, making all inhabitants into a single community. The early caliphs (successors to Muhammed) remained in Medina, making it the capital of the new Islamic empire until 661. A pilgrimage to Medina is often made in conjunction with the pilgrimage to Mecca in order to visit the tombs and shrines of Muhammed, his family and the first three caliphs.