When Imam Ali (a.s.) became Khalifa, he decided to remove Mu'awiya immediately, notwithstanding Mu'awiya's strong base of support. At that time, Mu'awiya had been the governor of Syria, Palestine, and Jordan for 17 years. Mu'awiya became defiant, he refused to obey Ali's orders. Brazen and unabashed, he even declined to recognize Ali or give allegiance of loyalty to him. Also in defiance, Mu'awiya established a parallel government in Greater Syria, and started a campaign of treacherous accusations and malicious rumors against Imam Ali (a.s.). He falsely blamed Imam Ali for the killing of Uthman, the third Khalifa, and urged people to take up arms against the Imam. He spread these notorious accusations constantly to incite an uprising against Ali (a.s.).
At the same time A'isha, the Prophet's widow, became highly vocal against Imam Ali (a.s.). She called for taking revenge for the blood of Uthman. As a result, a party of 3,000 insurgents supported by Sahaaba (Companions) such as Talha and Zubair, along with A'isha headed toward Basrah. The insurgents upon reaching Basrah clashed with the local authorities and finally occupied a portion of Basrah. Soon after the occupation these insurgents spread a reign of terror among the people, killing no less than 600 local Muslims, pilfering the treasury and stealing the arms supplies of the armory.
As a Khalifa in charge, Imam Ali (a.s.) could not ignore the situation, he had to act and restore peace and order. He ordered his forces to proceed to Basrah. As the Imam's forces reached near Basrah, Imam Ali (a.s.) tried to persuade the insurgents led by A'isha, Zubair and Talha to change their minds and avoid confrontation, but he did not succeed. A battle broke out though Zubair elected not to fight. Talha was wounded then bled to death. Thousands of people lost their lives. A'isha fell down from the camel after it was disabled; but luckily she was not hurt. Imam Ali asked Muhammad ibn Abu Bakr, (A'isha's brother), to take A'isha to Basrah for a few days, and from there to escort her to Medina with full honor and dignity. Upon leaving Basrah Al-Hasan (a.s.) and Al-Husain (a.s.) accompanied the Prophet's widow for some distance before bidding her farewell. Imam Ali (a.s.) stayed in Basrah for a few weeks to restore law and order. He compensated for the dead, and decided to forgive and absolve all who fought against him, exactly as the Prophet (pbuh) had done when he triumphed over Mecca 40 years earlier.