His ancestry from the early Sasanian family probably also played a role. Kartir was one of those nobles who supported Narseh, which is attested in the Paikuli inscription. Narseh's reign marked the return to the policy of religious tolerance which had been practiced by his father.
Kartir, a noble with ancestry from the early Sasanian family, supported Narseh, as documented in the Paikuli inscription.  Narseh's rule brought back the practice of religious tolerance that was established by his father.