The Umayyad Caliphate at its height, c. 732
A caliphate is an Islamic community led by a caliph, a person considered to be the religious successor to Muhammad, analagous to a pope in Christianity. The caliphates have spread Islam throughout their lands and instituted sharia law, the laws that Muhammad had decreed in the Quran. Historically, there have been four major caliphates since 632: the Rashidun Caliphate (632-661), Umayyad Caliphate (661-750), Abbasid Caliphate (750-1517), and Ottoman Empire (1517-1922). Since 1922, there has not been an Islamic ruler recognized as a caliph, but in 2014 the Islamic State jihadist group's leader Abu Bakr al-Baghdadi proclaimed himself the Caliph in a controversial statement not recognized by any countries and disputed by many Islamic scholars.