, the founder of the
Sasanian Empire On his coinage, the first Sasanian
King of Kings (
shahanshah)
Ardashir I (), introduces himself as King of Kings of a realm that he identified as
Eran. His son and successor Shapur I () calls himself King of Kings of
Eran and
Aneran in his
SKZ inscription. According to the inscription,
Eran was made up of the following provinces (
shahr in
Middle Persian): A similar list is mentioned in the
Ka'ba-ye Zartosht of the 3rd-century Zoroastrian priest
Kartir. The provinces of the late Sasanian realm are listed in the
Bundahishn and
Vendidad. Provinces were split into smaller administrative divisions, particularly the
khwarrah (same origin as the Iranian/Zoroastrian concept
khwarrah, "glory/fortune"),
rostag or
tasug (districts), and
dehs (villages). These divisions were not always used all over the realm, and records of other units are known, such as an
awestam, which was ostensibly akin to a
shahr and was administered by an
awestamdar. During the reforms of
Kavad I () and his son and successor
Khosrow I (), the provinces were grouped into four frontier regions (
kusts), with a marshal (
spahbed) in charge of each district; a chancery was also added to keep the soldiers equipped. Before Kavad and Khosrow's reforms, the Iranians' general (
Eran-spahbed) managed the empire's army. A new priestly office was also created known as the "advocate and judge of the poor" (
driyōšān jādag-gōw ud dādwar), which assisted the clergy to help the poor and underprivileged (an obligation they had possibly ignored previously). ==Hierarchical list of Sasanian administrators and their level of authority==