quality:corruption, structural:summarization, information:filtering
Reestablishment in Egypt

As early as 656/57, Amr and Mu'awiya persuaded Ibn Abi Hudhayfa, who had seized control of Egypt after Uthman's assassination, to meet them in al-Arish, where they took him captive in a ruse. Amr and Mu'awiya did not advance further than this point and Ibn Abi Hudhayfa was executed. Ali's second governor in Egypt, Qays ibn Sa'd, was dismissed in late 657 due to concerns that he would defect to Mu'awiya and his next appointee, Malik ibn al-Harith, died in Qulzum (Suez) on his way to the province. Malik's replacement was Muhammad ibn Abi Bakr, son of the first caliph and a foster son of Ali. Ibn Abi Bakr burned the homes and arrested the families of pro-Uthman mutineers from the Fustat garrison led by Mu'awiya ibn Hudayj and Maslama ibn Mukhallad. The latter two requested intervention by Mu'awiya, who dispatched Amr to Egypt with a 4,000–6,000-strong army. Despite his thirteen-year absence from Egypt, Amr nonetheless mustered the support of Egypt's original Arab military settlers and their sons. In July/August 658, his forces defeated Ali's troops at the Battle of al-Musannah between Heliopolis (Ain Shams) and Fustat. He subsequently captured Fustat. Ibn Hudayj pursued and captured Ibn Abi Bakr and had him executed over the objections of Amr, who had been lobbied by Ibn Abi Bakr's brother Abd al-Rahman to spare his life.

As per his agreement with Mu'awiya, Amr was installed as governor of Egypt for life and ruled as a virtual partner rather than a subordinate of Mu'awiya, who had become caliph after Ali's assassination and his son Hasan 's abdication in 661. On 22 January of that year, Amr escaped an assassination attempt by the Kharijite Zadawayh or Amr ibn Bakr, who killed Amr's stand-in for the Friday prayers, Kharija ibn Hudhafa, mistaking the latter for Amr. When the Kharijite was apprehended and brought before him, Amr proclaimed "You wanted me, but God wanted Kharija!" and he personally executed him.

Amr was permitted by the Caliph to retain personally the surplus revenues of the province after the payment of the troops' stipends and other government expenses. He increased the original garrison at Fustat, numbering some 15,000 soldiers, with the Syrian troops he brought with him. According to the historian Clive Foss "Amr ruled the country successfully, and with considerable independence and privilege, until his death".