A caliphate (Arabic: خِلافة khilāfah) is a state under the leadership of an Islamic steward with the title of caliph (/
Prior to the rise of Muhammad and the unification of the tribes of Arabia under Islam, Arabs followed a pre-Islamic Arab polytheism, lived as self-governing sedentary and nomadic communities and often raided their neighbouring tribes. Following the early Muslim conquests of the Arabian Peninsula, the region became unified and most of the tribes adopted Islam.
The first caliphate, the Rashidun Caliphate, was established immediately after Muhammad's death in 632. The four Rashidun caliphs, who directly succeeded Muhammad as leaders of the Muslim community, were chosen through shura, a process of community consultation that some consider to be an early form of Islamic democracy. The fourth caliph, Ali, who, unlike the prior three, was from the same clan as Muhammad (Banu Hashim), is considered by Shia Muslims to be the first rightful caliph and Imam after Muhammad. Ali reigned during the First Fitna (656–661), a civil war between supporters of Ali and supporters of the assassinated previous caliph, Uthman, from Banu Umayya, as well as rebels in Egypt; the war led to the establishment of the Umayyad Caliphate under Muawiyah I in 661.
The second caliphate, the Umayyad Caliphate was ruled by Banu Umayya, a Meccan clan descended from Umayya ibn Abd Shams. The caliphate continued the Arab conquests, incorporating the Caucasus, Transoxiana, Sindh, the Maghreb and the Iberian Peninsula (Al-Andalus) into the Muslim world. The caliphate had considerable acceptance of the Christians within its territory, necessitated by their large numbers, especially in the region of Syria. Following the Abbasid Revolution from 746–750, which primarily arose from non-Arab Muslim disenfranchisement, the Abbasid Caliphate was established in 750.
The third caliphate, the Abbasid Caliphate was ruled by the Abbasids, a dynasty of Meccan origin which descended from Hashim, a great-grandfather of Muhammad, making them part of Banu Hashim, via Abbas, an uncle of Muhammad, hence the name. Caliph al-Mansur founded its second capital of Baghdad in 762 which became a major scientific, cultural and art centre, as did the territory as a whole during a period known as the Islamic Golden Age. From the 10th century, Abbasid rule became confined to an area around Baghdad. From 945 to 1157, the Abbasid Caliphate came under Buyid and then Seljuq military control. In 1250, a non-Arab army created by the Abbasids called the Mamluks came to power in Egypt. In 1258, the Mongol Empire sacked Baghdad, ending the Abbasid Caliphate, and in 1261 the Mamluks in Egypt re-established the Abbasid Caliphate in Cairo. Though lacking in political power, the Abbasid dynasty continued to claim authority in religious matters until the Ottoman conquest of Mamluk Egypt in 1517.
The fourth major caliphate, the Ottoman Caliphate, was established after their conquest of Mamluk Egypt in 1517. The conquest gave the Ottomans control over the holy cities of Mecca and Medina, previously controlled by the Mamluks. The Ottomans gradually came to be viewed as the de facto leaders and representatives of the Muslim world. Following their defeat in World War I, their empire was partitioned by the United Kingdom and French Third Republic, and on 3 March 1924, the first President of the Turkish Republic, Mustafa Kemal Atatürk, as part of his reforms, constitutionally abolished the institution of the caliphate. A few other states that existed through history have called themselves caliphates, including the Isma'ili Fatimid Caliphate in Northeast Africa (909–1171), the Umayyad Caliphate of Córdoba in Iberia (929–1031), the Berber Almohad Caliphate in Morocco (1121–1269) and the Fula Sokoto Caliphate in present-day northern Nigeria (1804–1903).
The Sunni branch of Islam stipulates that, as a head of state, a caliph may come to power in one of four ways: either through an election, through nomination, through a selection by a committee, or by force. Followers of Shia Islam, however, believe a caliph should be an Imam chosen by God from the Ahl al-Bayt (the "Family of the House", referring to Muhammad's family).