Rashidun Caliphate

The Rashidun Caliphate (Arabic: الخلافة الرّاشدة, romanized: al-Khilāfat ar-Rāshidah) was the early Islamic polity led by the first four successive caliphs (lit. "successors"): Abu Bakr, Umar, Uthman, and Ali, collectively known as the Rashidun, or 'Rightly Guided' caliphs. These early caliphs led the Muslim community (Ummah) from the death of the Islamic prophet Muhammad in 632 CE to the establishment of the succeeding Umayyad Caliphate in 661 CE.

The title Rashidun stems from the Sunni Islamic doctrine that the caliphs were 'rightly guided'. Endowed with superior piety and wisdom, their era is regarded in Sunni Islam as a 'golden age', second only to the lifetime of Muhammad in sanctity and in providing moral and religious guidance. Sunnis consider the 'rightly guided' reign of the first four caliphs as a model to be followed and emulated from a religious point of view. The term Rashidun is not used by Shi'as, who make up 10–15% of the global Muslim population, as they only consider Ali to have been a legitimate caliph and reject the first three caliphs as usurpers; while Ibadis only regard the first two caliphs, Abu Bakr and Umar, as rightly-guided caliphs.

The caliphate's first 25 years were characterized by rapid military expansion during which it became the most powerful economic and military force in West Asia and Northeast Africa. By the 650s, in addition to the Arabian Peninsula, the caliphate had subjugated the Levant and parts of Transcaucasia to the north; North Africa from Egypt to the edge of present-day Tunisia in the west; and regions stretching from the Iranian Plateau to parts of Central and South Asia in the east. The caliphate ended after five years of internal strife.

Following Muhammad's death in June 632, Muslim leaders debated who should succeed him. Unlike later caliphates which were ruled by hereditary dynasties, the Rashidun caliphs were either chosen by a small group of high-ranking companions of Muhammad in shūrā (lit. 'consultation') or nominated by their predecessor. Muhammad's close companion and father-in-law Abu Bakr (r. 632–634), of the Banu Taym, was elected the first caliph in Medina and presided over the conquest of the Arabian Peninsula. The only Rashidun caliph not to die by assassination, he was succeeded by Umar (r. 634–644) of the Banu Adi, who was also a close companion and father-in-law of Muhammad. During Umar's reign, the caliphate expanded at an unprecedented rate, conquering more than two-thirds of the Byzantine Empire and nearly the entire Sasanian Empire.

Following the assassination of Umar, Uthman (r. 644–656) of the Banu Umayya, who was a senior companion and son-in-law of Muhammad, was elected caliph. His reign oversaw the completion of the conquest of Persia in 651 and continued the military campaigns into Byzantine territories. Uthman was assassinated in June 656 and was succeeded by Ali (r. 656–661) of the Banu Hashim, the cousin and son-in-law of Muhammad, who moved the caliphate's capital to Kufa. Ali's accession to the caliphate triggered the First Fitna, a civil war ignited by the refusal of Uthman's Umayyad kinsman and the long-time governor of Syria, Mu'awiya ibn Abi Sufyan (r. 661–680) to recognize Ali's authority until Uthman's killers were brought to justice.

After the Battle of Siffin between Ali's Iraqi army and Mu'awiya's Syrian forces, which resulted in a stalemate and inconclusive arbitration, a faction of Ali's erstwhile supporters, known as the Kharijites, seceded and rebelled against both sides, opposing his decision to arbitrate with Mu'awiya. Following Ali's assassination by a Kharijite dissident in 661, Mu'awiya invaded Iraq with his Syrian army and compelled Ali's eldest son and successor Hasan—who had been chosen as caliph in Kufa—to abdicate in his favour. Mu'awiya then entered Kufa and received the pledge of allegiance from the Iraqis, thus founding the Umayyad Caliphate.