Assassination of Ali in the context of "Second Fitna"

Ali ibn Abi Talib (Arabic: عَلِيُّ بْن أَبِي طَالِب, romanized: ʿAlī ibn Abī Ṭālib) (c. 600 – 661 CE) was the fourth Rashidun caliph who ruled from 656 CE until his assassination in 661, as well as the first Shia Imam. He was the cousin and son-in-law of the Islamic prophet Muhammad. Born to Abu Talib ibn Abd al-Muttalib and Fatima bint Asad, Ali was raised by his elder cousin Muhammad and was among the first to accept his teachings.

Ali played a pivotal role in the early years of Islam when Muslims were severely persecuted in Mecca. After the immigration (hijra) to Medina in 622, Muhammad gave his daughter Fatima to Ali in marriage and swore a pact of brotherhood with him. Ali served as Muhammad's secretary and deputy in this period, and was the flag bearer of his army. Numerous sayings of Muhammad praise Ali, the most controversial of which was uttered in 632 at the Ghadir Khumm, "Whoever I am his mawla, then Ali is his mawla." The interpretation of the polysemous Arabic word mawla is disputed: For Shia Muslims, Muhammad thus invested Ali with his religious and political authority, while Sunni Muslims view this as a mere statement of friendship and rapport. When Muhammad died in the same year, a group of Muslims met in the absence of Ali and appointed Abu Bakr (r. 632–634) as their leader. Ali later relinquished his claims to leadership and resigned from public life during the reigns of Abu Bakr and his successor, Umar (r. 634–644). Even though his advice was occasionally sought, the conflicts between Ali and the first two caliphs are epitomized by his refusal to follow their practices. This refusal cost Ali the caliphate to the benefit of Uthman (r. 644–656), who was thus appointed to succeed Umar by the electoral council. Ali was also highly critical of Uthman, who was widely accused of nepotism and corruption. Yet Ali also repeatedly mediated between the caliph and the provincial dissidents angered by his policies.

Mu'awiya I (c. 597, 603 or 605–April 680) was the founder and first caliph of the Umayyad Caliphate, ruling from 661 until his death. He became caliph less than thirty years after the death of the Islamic prophet Muhammad and immediately after the four Rashidun ('rightly-guided') caliphs. Unlike his predecessors, who had been close, early companions of Muhammad, Mu'awiya was a relatively late follower of Muhammad.

Mu'awiya and his father Abu Sufyan had opposed Muhammad, their distant Qurayshite kinsman and later Mu'awiya's brother-in-law, until Muhammad captured Mecca in 630. Afterward, Mu'awiya became one of Muhammad's scribes. He was appointed by Caliph Abu Bakr (r. 632–634) as a deputy commander in the conquest of Syria. He moved up the ranks through Umar's caliphate (r. 634–644) until becoming governor of Syria during the reign of his Umayyad kinsman, Caliph Uthman (r. 644–656). He allied with the province's powerful Banu Kalb tribe, developed the defenses of its coastal cities, and directed the war effort against the Byzantine Empire, including the first Muslim naval campaigns. In response to Uthman's assassination in 656, Mu'awiya took up the cause of avenging the murdered caliph and opposed the election of Ali. During the First Muslim Civil War, the two led their armies to a stalemate at the Battle of Siffin in 657, prompting an abortive series of arbitration talks to settle the dispute. Afterward, Mu'awiya gained recognition as caliph by his Syrian supporters and his ally Amr ibn al-As, who conquered Egypt from Ali's governor in 658. Following the assassination of Ali in 661, Mu'awiya compelled Ali's son and successor Hasan to abdicate and Mu'awiya's suzerainty was acknowledged throughout the Caliphate.

The Kharijites (Arabic: الخوارج, romanized: al-Khawārij, singular Arabic: خارجي, romanized: khārijī) were an Islamic sect which emerged during the First Fitna (656–661). The first Kharijites were supporters of Ali who rebelled against his acceptance of arbitration talks to settle the conflict with his challenger, Mu'awiya, at the Battle of Siffin in 657. They asserted that "judgment belongs to God alone", which became their motto, and that rebels such as Mu'awiya had to be fought and overcome according to Qur'anic injunctions. Ali defeated the Kharijites at the Battle of Nahrawan in 658, but their insurrection continued. Ali was assassinated in 661 by a Kharijite dissident seeking revenge for the defeat at Nahrawan.

After Mu'awiya established the Umayyad Caliphate in 661, his governors kept the Kharijites in check. The power vacuum caused by the Second Fitna (680–692) allowed for the resumption of the Kharijites' anti-government rebellion, and the Kharijite factions of the Azariqa and Najdat came to control large areas in Persia and Arabia. Internal disputes and fragmentation weakened them considerably before their defeat by the Umayyads in 696–699. In the 740s, large-scale Kharijite rebellions broke out across the caliphate, but all were eventually suppressed. Although the Kharijite revolts continued into the Abbasid Caliphate (750–1258), the most militant Kharijite groups were gradually eliminated. They were replaced by the non-activist Ibadiyya, who survive to this day in Oman and some parts of North Africa. They, however, deny any links with the Kharijites of the Second Muslim Civil War and beyond, condemning them as extremists.

Hasan ibn Ali (Arabic: الحسن ابن علي, romanized: al-Ḥasan ibn ʿAlī; c. 625 – 2 April 670) was an Alid political and religious leader. The eldest son of Ali and Fatima and a grandson of the Islamic prophet Muhammad, Hasan briefly ruled as caliph from January 661 until August 661. He is considered as the second Imam in Shia Islam, succeeding Ali and preceding his brother Husayn. As a grandson of the prophet, he is part of the ahl al-bayt and the ahl al-kisa, and also participated in the event of the mubahala.

During the caliphate of Ali (r. 656–661), Hasan accompanied him in the military campaigns of the First Fitna. Following Ali's assassination in January 661, Hasan was acknowledged caliph in Kufa. His sovereignty was not recognized by Mu'awiya ibn Abi Sufyan (r. 661–680), the governor of Syria, who led an army into Kufa while pressing Hasan for abdication in letters. In response, Hasan sent a vanguard under Ubayd Allah ibn al-Abbas to block Mu'awiya's advance until he arrived with the main army. Meanwhile, Hasan was severely wounded in an abortive assassination attempt by the Kharijites, a faction opposed to both Ali and Mu'awiya. This attack demoralised Hasan's army and led to widespread desertion. Ubayd Allah and most of his troops also defected after Mu'awiya bribed him. In August 661, Hasan signed a peace treaty with Mu'awiya on the condition that the latter should rule in compliance with the Quran and the Sunnah, a council should appoint his successor, and Hasan's supporters would receive amnesty. Hasan retired from politics and abdicated in Medina where he died either from illness or poisoning, though the early sources are nearly unanimous that he was poisoned. Mu'awiya is commonly viewed as the instigator in the murder of Hasan, which removed an obstacle to the succession of his son Yazid I (r. 680–683).

Husayn ibn Ali (Arabic: الحسين بن علي, romanized: al-Ḥusayn ibn ʿAlī; 11 January 626 – 10 October 680 CE) was a social, political and religious leader in early medieval Arabia. The grandson of the Islamic prophet Muhammad and an Alid (the son of Ali ibn Abi Talib and Muhammad's daughter Fatima), as well as a younger brother of Hasan ibn Ali, Husayn is regarded as the third Imam in Shia Islam after his brother, Hasan, and before his son, Ali al-Sajjad. Husayn is a prominent member of the Ahl al-Bayt and is also considered to be a member of the Ahl al-Kisa and a participant in the event of the mubahala. Muhammad described him and his brother, Hasan, as the leaders of the youth of paradise.

During the caliphate of Ali, Husayn accompanied him in wars. After the assassination of Ali, he obeyed his brother in recognizing the Hasan–Mu'awiya I treaty, despite it being suggested to do otherwise. In the nine-year period between Hasan's abdication in AH 41 (660) and his death in AH 49 or 50 (669 or 670), Hasan and Husayn retreated to Medina, trying to keep aloof from political involvement for or against Mu'awiya I. After the death of Hasan, when Iraqis turned to Husayn, concerning an uprising, Husayn instructed them to wait as long as Mu'awiya was alive due to Hasan's peace treaty with him.