Abu Nasr, an expansionist, used the patronage of the ruler of Fars in order to defeat his old enemies. As Vassaf tells us, he and his soldiers boarded a ship to Kish and on 8 May 1229, invaded that island, killing Malik Sultān, its ruler, and putting an end to the local dynasty of Banu Qaissar, the old rulers of the island and the major power in the Persian Gulf region. The patronage of Fārs soon came to an end, the relationship between Abu Nasr and Abu Bakhr quickly souring. Abu Bakr thus conquered Hormuz, killed Abānasr, and annexed Hormuz to Fārs, changing the name of the city of Hormuz (known as Nāband) to Dēwānkhāna.