 Though Hasan Beg does not mention his involvement in succession matters after the death of Tahmasp I, contemporary author Abd-ol-Hossein Nava'i suggests that Hasan Beg sided with the other Rumlu's, who sought to install Prince Ismail Mirza (later known regnally as Ismail II; 1576–1577) on the throne and who were adversaries of the pro-Haydar Mirza camp.Nava'i suggests that Hasan Beg may have been part of the Rumlu "qurchis" who took part in the murder of Haydar Mirza.When Ismail II died in 1577, Hasan Beg became part of the royal retinue of his successor, Mohammad Khodabanda (1578–1587).