 The Parthian nobility worked for the Sasanian shah for personal benefit, personal oath, and, conceivably, a common awareness of the "Aryan" (Iranian) kinship they shared with their Persian overlords.Use of war elephants is also attested under Shapur, who made use of them to demolish the city of Hatra.He may also have used them against Valerian, as attested in the "Shahnameh" ("The Book of Kings").