The Fatimid Caliphate or Fatimid Empire was a caliphate extant from the tenth to the twelfth centuries CE under the rule of the Fatimids, an Isma'ili Shia dynasty. Spanning a large area of North Africa and West Asia, it ranged from the western Mediterranean in the west to the Red Sea in the east. The Fatimids trace their ancestry to the Islamic prophet Muhammad's daughter Fatima and her husband Ali, the first Shia imam. The Fatimids were acknowledged as the rightful imams by different Isma‘ili communities as well as by denominations in many other Muslim lands and adjacent regions. Originating during the Abbasid Caliphate, the Fatimids conquered Ifriqiya and established the city of al-Mahdiyya. The Fatimid dynasty ruled territories across the Mediterranean coast and ultimately made Egypt the center of the caliphate. At its height, the caliphate included—in addition to Egypt—varying areas of the Maghreb, Sicily, the Levant, and the Hejaz.

A caliphate or khilāfah is an institution or public office under the leadership of an Islamic steward with the title of caliph, a person considered a political-religious successor to the Islamic prophet Muhammad and a leader of the entire Muslim world (ummah). Historically, the caliphates were polities based on 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 (750–1517). In the fourth major caliphate, the Ottoman Caliphate, the rulers of the Ottoman Empire claimed caliphal authority from 1517 until the caliphate was formally abolished as part of the 1924 secularisation of Turkey. Throughout the history of Islam, a few other Muslim states, almost all of which were hereditary monarchies such as the Mamluk Sultanate and Ayyubid Sultanate, have claimed to be caliphates.