[1] The young Sasanian king Yazdegerd III (r. 632-651) supported him in these raids, and believed that it was possible to regain the territories which had been taken by the Arabs.

[2] After some time, Hormuzan clashed with an Arab army to the west of Hormizd-Ardashir, but was easily defeated and retreated back to the city, where he asked for peace.

[3] However, he soon stopped paying tribute, and raised an army of Kurds (a term then used to describe Iranian nomads).

Fortunately for Hormuzan, Shushtar was well fortified due to the rivers and canals that surrounded it on almost all sides.

Al-Nu'man agreed, and Sina told him the following thing; "attack via the outlet of the water, and then you will conquer the city.

[6] According to al-Baladhuri, during the siege, the Arabs were reinforced with a group of professional Iranian elites under Siyah al-Uswari, known as the Asawira.

According to al-Tabari and al-Baladhuri, Abu Musa Ashaari marched to Gundishapur and besieged the city in 642.

However, some inhabitants of the city refused to live under the rule of the Rashidun Caliphate, and fled to Kalbaniyah.