The siege of Gundishapur took place in 642. It was the last major city in Khuzestan to fall to the Arabs. According to al-Tabari and

al-Baladhuri ʾAḥmad ibn Yaḥyā ibn Jābir al-Balādhurī ( ar, أحمد بن يحيى بن جابر البلاذري) was a 9th-century Muslim historian. One of the eminent Middle Eastern historians of his age, he spent most of his life in Baghdad and e ...

, the Arab general

Abu Musa Ashaari Abu Musa Abd Allah ibn Qays al-Ash'ari ( ar, أبو موسى عبد الله بن قيس الأشعري, Abū Mūsā ʿAbd Allāh ibn Qays al-Ashʿarī), better known as Abu Musa al-Ash'ari ( ar, أبو موسى الأشعري, Abū Mūsā al-Ash ...

marched to Gundishapur and besieged the city. The cities defences were weak and after a few days the city surrendered and opened its gate. Abu Musa then made peace with the city in return for tribute, which the city accepted. However, some inhabitants of the city refused to live under the rule of the Rashidun Caliphate, and fled to Kalbaniyah. Abu Musa then went to the city and easily seized it. He thereafter seized a few other small cities, thus completing the conquest of Khuzestan.

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* Gundishapur Gundishapur Gundishapur Muslim conquest of Persia {{siege-stub