What events led to the first fitnah in the Muslim community?

The first fitnah (656–661 CE) was a pivotal internal struggle that resulted in civil war and a lasting religious schism within the Muslim community. The conflict was precipitated by several key events:1

• Assassination of Uthman: The third caliph, Uthman, faced opposition for favoring his own Meccan family in official appointments. His murder by Egyptian soldiers in 656 created a power vacuum and urgent demands for vengeance.12
• Contested Succession: When Ali was proclaimed the fourth caliph, he faced immediate challenges from those demanding justice for Uthman, including Muʿāwiyah I, the governor of Syria and a kinsman of Uthman.123
• Battle of the Camel: This initial confrontation pitted Ali against a coalition of prominent figures, including Aishah, Talhah, and Zubayr, marking the start of civil war.12
• Battle of Siffin and Arbitration: The conflict between Ali and Muʿāwiyah culminated at the Battle of Siffin in 657. Ali’s decision to accept human arbitration weakened his authority and led to the emergence of the Khawārij, who rejected the process.13

The war concluded in 661 following Ali’s assassination, allowing Muʿāwiyah to establish the Umayyad dynasty.13