Shapur's eldest son had succeeded him as the Sassanian ruler at his death in 272, ruling as Hormizd Ardashir, but he reigns only a year; another of Shapur's sons now succeeds him, ruling as Bahram.

Kartir Hangirpe, a highly influential Zoroastrian high priest, had risen to power during the reign of Shapur, to whom he had served as advisor and accompanied on travels.

Hormizd had appointed Kartir Moabadan-Moabad, 'priest of priests', a position Kartir has ruthlessly used to promote his own position and to punish lower ranking priests whose opinions he considers contrary to his own.

The influential Kartir has called for the persecution of adherents of other religions, in particular Manichaeans.

Under the guidance of Kartir, Bahram has had the prophet Mani, the founder of Manichaeism (and the author of the Shapurgan, which was dedicated to Bahram's father Shapur) sentenced to death.

Mani dies in his cell shortly before his execution.

However, rumors persist that Mani might have been flayed alive and his skin, stuffed with straw, suspended for some time over one of the gates of the great city of Shapur.

On Bahram’s orders, the prophet's death is followed by the persecution of his disciples.

Manichaeism is relatively well established by that time, and is supported by numerous priests under a hierarchy of religious leaders that include twelve apostles and seventy-two bishops.

Nearly all of them are handed over to the Zoroastrian clergy, who—under Kartir —consider Manichaeism a heresy and cause the followers of Mani to be executed or otherwise punished.

When Bahram dies, possibly of disease, later in 276, his son ascends the throne to rule as Bahram II; he will continue his predecessors' work of strengthening dynastic power as opposed to the nobility.