After Prophet Muhammad peace be upon him died, a series of Caliphs governed the Islamic State: Abu Bakr, Umar, Usman, and Ali. These first Caliphs are popularly known as the "Rashidun" or "rightly-guided" Caliphs. After the Rashidun, a series of Caliphates were established. Each caliphate was like a monarchy, developed its own unique laws and adopted a particular sect of Islam as a State religion. Until the ninth century C.E. the Muslim World would remain a single political entity under the leadership of one Caliph. The early Caliphate is also known as the Arab Empire or Islamic Empire.

A caliphate is the political leadership of the Muslim ummah in classical and medieval Islamic history and juristic theory. The head of state's position (Caliph) is based on the notion of a successor to the Islamic prophet Muhammad's political authority.

According to Sunnis the Caliph should be from Quraysh decendency (the tribe of the Prophet Muhammad) and elected by Muslims or their representatives; and according to Shia Islam, is an Imam descended in a line from the Ahl al-Bayt. From the time of Muhammad until 1924, successive and contemporary caliphates were held by various dynasties, including the Umayyads (who were driven from Damascus to Córdoba), the Abbasids (who ruled from Baghdad and drove away the Umayyads from Damascus), the Fatimids (who ruled from Cairo), and finally the Ottomans.

The caliphate is the only form of governance that has full approval in traditional Islamic theology, and "is the core political concept of Sunni Islam, by the consensus of the Muslim majority in the early centuries."