His own inscriptions at Naqsh-e Rajab, Naqsh-e Rostam and Sar Mashhad, the only sources for his biography, describe his career and titles under Ardashir I through Bahram II but never state where he was born.
What would resolve this A Sasanian era inscription or record naming his origin, which none of his own surviving inscriptions supplies.
OpenSasanian history; Zoroastrian studies; Middle Persian epigraphyTouraj Daryaee, Sasanian Persia: The Rise and Fall of an Empire