 When Yazdegerd I's brother Bahram IV () was assassinated in 399, he succeeded him.Yazdegerd I inherited an empire which had been through tumultuous times; his three previous predecessors, Bahram IV, Shapur III and Ardashir II, had been murdered by the nobility.Most of the nobility belonged to the powerful Parthian noble families (known as the "wuzurgan") who were centered on the Iranian Plateau.