Who Were the Caliphs?

A caliph is a religious leader in Islam, believed to be the successor to the Prophet Muhammad. The caliph is the head of the "ummah," or the community of the faithful. Over time, the caliphate became a religiopolitical position, in which the caliph ruled over the Muslim empire.

The word "caliph" comes from the Arabic "khalifah," meaning "substitute" or "successor." Thus, the caliph succeeds the Prophet Muhammad as the leader of the faithful. Some scholars argue that in this usage, khalifah is closer in meaning to "representative" — that is, the caliphs weren't really substituted for the Prophet but merely represented Muhammad during their time on earth.

Contention of The First Caliphate

The original schism between Sunni and Shi'a Muslims occurred after the Prophet died, because of a disagreement over who should be the caliph. Those who became the Sunnis believed that any worthy follower of Muhammad could be caliph and they backed the candidacies of Muhammad's companion, Abu Bakr, and then of Umar when Abu Bakr died. The early Shi'a, on the other hand, believed that the caliph should be a close relative of Muhammad. They preferred the Prophet's son-in-law and cousin, Ali.

After Ali was assassinated, his rival Mu-waiyah established the Umayyad Caliphate in Damascus, which went on to conquer an empire stretching from Spain and Portugal in the west through North Africa and the Middle East to Central Asia in the east. The Umayyads ruled from 661 to 750, when they were overthrown by the Abbasid Caliphs. This tradition continued well into the next century.

Conflict Over Time and The Last Caliphate

From their capital at Baghdad, the Abbasid caliphs ruled from 750 to 1258, when the Mongol armies under Hulagu Khan sacked Baghdad and executed the caliph. In 1261, the Abbasids regrouped in Egypt and continued to exert religious authority over the Muslim faithful of the world until 1519.

At that time, the Ottoman Empire conquered Egypt and moved the caliphate to the Ottoman capital at Constantinople. This removal of the caliphate from the Arab homelands to Turkey outraged some Muslims at the time and continues to rankle with some fundamentalist groups to this day.

The caliphs continued as heads of the Muslim world — though not universally recognized as such, of course — until Mustafa Kemal Ataturk abolished the caliphate in 1924. Although this move by the newly secular Republic of Turkey sparked an outcry among other Muslims around the world, no new caliphate has ever been recognized.

Dangerous Caliphates of Today

Today, the terrorist organization ISIS (the Islamic State of Iraq and Syria) has declared a new caliphate in the territories it controls. This caliphate is not recognized by other nations, but the would-be caliph of ISIS-ruled lands is the organization's leader, al-Baghdadi.

ISIS currently wants to revive the caliphate in the lands that once were the home of the Umayyad and Abbasid Caliphates. Unlike some of the Ottoman caliphs, al-Baghdadi is a documented member of the Quraysh clan, which was the Prophet Muhammad's clan.

This gives al-Baghdadi legitimacy as a caliph in the eyes of some Islamic fundamentalists, despite the fact that most Sunnis historically did not require a blood relationship to the Prophet in their candidates for the caliph.