ISIS leader urges Muslims to join Islamic caliphate in Iraq & Syria - BBC News
ISIL renames itself "Islamic State" and declares Caliphate in captured territory
Rise and fall of the Islamic State group’s “caliphate”
Islamic caliphate declared by Isis | Channel 4 News
Islamic State Families in Syria Flee Group's Last Stronghold as “Caliphate” Fights to Death
A caliphate is a state under the leadership of an Islamic steward with the title of caliph, a person considered a religious successor to the Islamic prophet Muhammad and a leader of the entire ummah (community). Historically, the caliphates were polities based
in Islam which developed into multi-ethnic trans-national empires. During the medieval period, three major caliphates succeeded each other: the Rashidun Caliphate (632–661), the Umayyad Caliphate (661–750) and the Abbasid Caliphate (750–1258). In the fourth major caliphate, the Ottoman Caliphate, the rulers of the Ottoman Empire claimed caliphal authority from 1517. During the history of Islam, a few other Muslim states, almost all hereditary monarchies, have claimed to be caliphates.