The Second Fitna was a period of general political and military disorder and civil war in the Islamic community during the early Umayyad Caliphate. It followed the death of the first Umayyad caliph Mu'awiya I in 680, and lasted for about twelve years. The war involved the suppression of two challenges to the Umayyad dynasty, the first by Husayn ibn Ali, as well as his supporters including Sulayman ibn Surad and Mukhtar al-Thaqafi who rallied for his revenge in Iraq, and the second by Abd Allah ibn al-Zubayr.
The roots of the civil war go back to the First Fitna. After the assassination of the third caliph, Uthman, the Islamic community experienced its first civil war over the question of leadership, with the main contenders being Ali and Mu'awiya. Following the assassination of Ali in 661 and the abdication of his successor Hasan the same year, Mu'awiya became the sole ruler of the caliphate. Mu'awiya's unprecedented move to nominate his son Yazid as his heir sparked opposition, and tensions soared after Mu'awiya's death. Husayn ibn Ali was invited by the pro-Alids of Kufa to overthrow the Umayyads but was killed with his small company en route to Kufa at the Battle of Karbala in October 680. Yazid's army assaulted anti-government rebels in Medina in August 683 and subsequently besieged Mecca, where Ibn al-Zubayr had established himself in opposition to Yazid. After Yazid died in November the siege was abandoned, and Umayyad authority collapsed throughout the caliphate except in certain parts of Syria; most provinces recognized Ibn al-Zubayr as caliph. A series of pro-Alid movements demanding revenge for Husayn's death emerged in Kufa, beginning with Ibn Surad's Penitents movement, which was crushed by the Umayyads at the Battle of Ayn al-Warda in January 685. Kufa was then taken over by Mukhtar. Though his forces routed a large Umayyad army at the Battle of Khazir in August 686, Mukhtar and his supporters were slain by the Zubayrids in April 687 following a series of battles. Under the leadership of Abd al-Malik ibn Marwan, the Umayyads reasserted control over the caliphate after defeating the Zubayrids at the Battle of Maskin in Iraq and killing Ibn al-Zubayr in the siege of Mecca in 692.
Abd al-Malik made key reforms in the administrative structure of the caliphate, including increasing caliphal power, restructuring the army, and Arabizing and Islamizing the bureaucracy. The events of the Second Fitna intensified sectarian tendencies in Islam, and various doctrines were developed within what would later become the Sunni and Shi'a denominations of Islam.
Background
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 early caliphs belonged), led by Muhammad's prominent companions Talha ibn Ubayd Allah and Zubayr ibn al-Awwam, 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. 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.