The head of state in Sasanian Iran was the king. Ardashir I adopted the title “King of Kings” (Persian: shahanshah), which was traditional in the Ancient Near East. This title largely reflected reality: in its early history, the Sasanian Empire consisted substantially of vassal principalities ruled by local kings. Though subordinate to the Persians, these rulers retained a degree of autonomy.
The system of central governing bodies — like many other spheres of life — remained rooted in traditions, institutions, and principles inherited from the overthrown Arsacid dynasty until the mid‑6th century CE. In this respect, the Sassanids were pragmatic traditionalists: they were reluctant to change what did not urgently require alteration.
For the first three centuries of its existence, the key organizing principle of the Sasanian administrative system was hereditary status. Appointments to both civil and military positions depended on the candidate’s noble lineage. Until the reign of Khosrow the Great, an ancient Parthian tradition prevailed: each senior office was held by members of specific aristocratic families and was, in a sense, treated as hereditary property of that noble house.
In Russian historical tradition, a similar phenomenon existed and is well known to every school student as mestnichestvo.
Local power also rested with native noble families — a Persian equivalent of “boyars” — who united both Persians and descendants of Parthians who had voluntarily sided with Ardashir I. Their considerable independence from the central authority is evidenced by the fact that one category of these local rulers bore the title “shah” — i.e., king.
Thus, in administrative and territorial terms, Sasanian Iran during the 3rd–6th centuries CE was a conglomerate of semi‑autonomous (and sometimes merely nominally dependent) domains. An example is the so‑called Kushanshahr on Iran’s eastern border (in what is now Afghanistan).
Such a system inevitably provoked discontent among Sasanian kings seeking to strengthen their personal authority. The first ruler to attempt curbing the overly independent Persian aristocrats was Kavad (488–531 CE), but his death prevented him from completing this task. The decisive confrontation with the Persian hereditary nobility occurred under Kavad’s son — Khosrow I the Great.
Khosrow succeeded in ending aristocratic lawlessness by implementing administrative and other reforms, thereby bringing order to the state. The model of civil and military administration established by Khosrow Anushirvan enabled the Persians to nearly defeat Byzantium in the war of 602–628 CE. However, this system’s resources proved insufficient to protect Iran from the Arab conquest in the mid‑7th century.
