The name of Hormizd (also spelled Ōhrmazd, Hormozd) is the Middle Persian version of the name of the supreme deity in Zoroastrianism, known in Avestan as Ahura Mazda.

[3][4] Hormizd III was the eldest son and heir of the Sasanian shah Yazdegerd II, and governed the eastern province of Sakastan during his father's reign.

[5] The province was far away from the imperial court in Ctesiphon, and had since its conquest by Ardashir I (r. 224–240) been governed by Sasanian princes, who held title of sakanshah ("king of the Saka").

[7] His younger brother Peroz I, with the support of the powerful Mihranid magnate Raham Mihran, fled to the northeastern part of the empire and began raising an army in order to claim the throne for himself.

However, this is most likely a legend, due to being contradicted by other sources, which state Peroz had Hormizd and three members of his family killed.