After the third caliph Uthman's assassination by rebels in 656, the rebels and the townspeople of Medina declared Ali, a cousin and son-in-law of the Islamic prophet Muhammad, caliph. Most of the Quraysh (the grouping of Meccan clans to which Muhammad and all the three caliphs belonged), led by Muhammad's prominent companions Talha ibn Ubayd Allah and Zubayr ibn al-Awam, and Muhammad's widow A'isha, refused to recognize Ali. They called for revenge against Uthman's killers and the election of a new caliph through shura (consultation). These events precipitated the First Fitna (First Muslim Civil War). Ali emerged victorious against these early opponents at the Battle of the Camel near Basra in November 656, thereupon moving his capital to the Iraqi garrison town of Kufa. Mu'awiya, the governor of Syria, and a member of the Umayyad clan to which Uthman belonged, also denounced Ali's legitimacy as caliph and the two confronted each other at the Battle of Siffin. The battle ended in a stalemate in July 657 when Ali's forces refused to fight in response to Mu'awiya's calls for arbitration. Ali reluctantly agreed to talks, but a faction of his forces, later called the Kharijites, broke away in protest, condemning his acceptance of arbitration as blasphemous. Arbitration could not settle the dispute between Mu'awiya and Ali. The latter was assassinated by a Kharijite in January 661, after Ali's forces had killed most of the Kharijites at the Battle of Nahrawan. Ali's eldest son Hasan became caliph, but Mu'awiya challenged his authority and invaded Iraq. In August, Hasan abdicated the caliphate to Mu'awiya in a peace treaty, thus ending the First Fitna. The capital was transferred to Damascus.
The main campaigns and battles of the Second Fitna
The treaty brought a temporary peace, but no framework of succession was established. As it had in the past, the issue of succession could potentially lead to problems in the future. The orientalist Bernard Lewis writes: "The only precedents available to Mu'āwiya from Islamic history were election and civil war. The former was unworkable; the latter had obvious drawbacks." Mu'awiya wanted to settle the issue in his lifetime by designating his son Yazid as his successor. In 676, he announced his nomination of Yazid. With no precedence in Islamic history, hereditary succession aroused opposition from different quarters and the nomination was considered the corruption of the caliphate into monarchy. Mu'awiya summoned a shura in Damascus and persuaded representatives from various provinces by diplomacy and bribes. The sons of a few of Muhammad's prominent companions including Husayn ibn Ali, Abd Allah ibn al-Zubayr, Abd Allah ibn Umar and Abd al-Rahman ibn Abi Bakr, all of whom, by virtue of their descent, could also lay claim to the caliphal office, opposed the nomination. Mu'awiya's threats and the general recognition of Yazid throughout the caliphate forced them into silence.
Historian Fred Donner writes that contentions over the leadership of the Muslim community had not been settled in the First Fitna and resurfaced with the death of Mu'awiya in April 680. Before his death, Mu'awiya cautioned Yazid that Husayn and Ibn al-Zubayr might challenge his rule and instructed him to defeat them if they did. Ibn al-Zubayr, in particular, was considered dangerous and was to be treated harshly, unless he came to terms. Upon his succession, Yazid charged the governor of Medina, his cousin Walid ibn Utba ibn Abi Sufyan, to secure allegiance from Husayn, Ibn al-Zubayr and Ibn Umar, with force if necessary. Walid sought the advice of his kinsman Marwan ibn al-Hakam. He counseled that Ibn al-Zubayr and Husayn should be forced to give allegiance as they were dangerous, while Ibn Umar should be left alone since he posed no threat. Walid summoned the two, but Ibn al-Zubayr escaped to Mecca. Husayn answered the summons but declined to give allegiance in the secretive environment of the meeting, suggesting it should be done in public. Marwan threatened to imprison him, but due to Husayn's kinship with Muhammad, Walid was unwilling to take any action against him. A few days later, Husayn left for Mecca without giving allegiance. In the view of the Islamicist G. R. Hawting, "... tensions and pressures which had been suppressed by Mu'awiya came to the surface during Yazid's caliphate and erupted after his death, when Umayyad authority was temporarily eclipsed."