The Modern Persian word Īrān (ایران) derives immediately from Middle Persian Ērān (Pahlavi spelling: ʼyrʼn), first attested in an inscription that accompanies the investiture relief of the first Sassanid king Ardashir I at Naqsh-e Rustam.[3] In this inscription, the king's Middle Persian appellation is ardašīr šāhān šāh ērān while in the Parthian language inscription that accompanies the Middle Persian one the king is titled ardašīr šāhān šāh aryān (Pahlavi: ... ʼryʼn) both meaning king of kings of Iranians.