 During the reign of Shapur, a certain Papak served as the commander of the royal guard ("hazarbed"), while Peroz served as the chief of the cavalry ("aspbed"); Vahunam and Shapur served as the director of the clergy; Kirdisro served as viceroy of the empire ("bidaxsh"); Vardbad served as the "chief of services"; Hormizd served as the chief scribe; Naduk served as "the chief of the prison"; Papak served as the "gate keeper"; Mihrkhwast served as the treasurer; Shapur served as the commander of the army; Arshtat Mihran served as the secretary; Zik served as the "master of ceremonies".Under Shapur, the Iranian military experienced a resurge after a rather long decline in the 2nd and 3rd centuries, which gave the Romans the opportunity to undertake expeditions into the Near East and Mesopotamia during the end of the Parthian Empire.Yet, the military was essentially the same as that of the Parthians; the same Parthians nobles who served the Arsacid royal family, now served the Sasanians, forming the majority of the Sasanian army.