 This development threatened the position of Justan, but in the ensuing showdown between the two Hasan was able to affirm his position and compel Justan to swear allegiance to himself.Justan was murdered in 919 by his brother Ali of Dailam, who became the new ruler of the Justanid dynasty.However, Justan's murder was shortly avenged by his son-in-law Muhammad ibn Musafir who had married his daughter Kharasuya and was from another Dailamite dynasty known as the Sallarids, a dynasty which ruled over Tarum.