 According to the medieval historians Ibn al-Balkhi and Hamza al-Isfahani, he was known as "Yazdegerd the Gentle" ("Yazdegerd-e Narm").However, the favorable account of Yazdegerd II is due to his policy of persecuting non-Zoroastrians within the empire, which appeased the Iranian aristocracy and especially the Zoroastrian priesthood, which sought to use the Sasanian Empire to impose their authority over the religious and cultural life of its people.This is the opposite of the policy of his grandfather and namesake, Yazdegerd I (known as the "sinner"), who is the subject of hostility in Persian sources due to his tolerant policy towards his non-Zoroastrian subjects, and his refusal to comply with the demands of the aristocracy and priesthood.