The administration orders and structures of the Parthian and Sasanian powers are almost exactly repeating the models of Achaemenid governance. Various evidence and facts have been preserved about that, especially about the Sasanian power. According to them, this power was divided into five administrative-territorial units with “Center + 4 peripheral regions” principle.

KeywordsAchaemenid power Parthian power Sasanian power Darius I Ardashir I Shapur I Elam Kul-e Farah Sumer Urnanshe Greater Armenia Tigran the Great Bundahišn “Armenian geography” spahbed pitiaxae.