About the first half of 5th A.D., the Bani Qaisar kings of Kish succeeded in establishing a local government in Kish Island. In addition, in the late of 5th and the early of 6th centuries A.H., they had the intention of extending their influence all over the Persian Gulf, specially in Bahrein Islands, in the southern coast of the Persian Gulf. Since the year of 469 A.H., the local governments rose to power in Bahrein region, who, because of their founder name, Amir Abdullah b. Ali al-Oyuni, were known as Oyunid rulers. They ruled two centuries (469-636A.H.), on some regions such as al-Ahasa, Qatif and Awal. In the late of 5th century or the early of 6th century A.H., they arranged some attacks from Kish to Bahrein and finally the Oyunid rulers had to obey them.
This study aims to investigate political and economic relations between the Bani Qaisar kings of Kish and Oyunid rulers of Bahrein and analysis the outcomes of this relationships. So by using descriptive-analytical method and primary sources, it has been indicated that Oyunid rulers of Bahrein obeyed Bani Qaisar kings of Kish both economically and politically.