The previous Sasanian shahs had pursued a policy of religious tolerance towards the non-Zoroastrian minorities in the empire.
However, with Bahram I's accession to the throne, and the rise of the authority of the Zoroastrian priesthood and the increasing influence of Kartir, this changed; when Mani reached the city of Gundishapur, much uproar occurred, in the same fashion as Jesus' entry into Jerusalem.
Kartir, along with other Zoroastrian priests protested and made Bahram I have Mani imprisoned and sentenced to death in 274.

Mani's death was followed by the persecution of his followers by Kartir and the Zoroastrian clergy, who used the persecution of religious minorities as a method to increase and spread their vast influence.
Mani was seen by the Zoroastrian clergy as heterogeneous philosopher and a threatening pagan who was presenting an obscure perception of Zoroastrianism, which had been tainted by non-Zoroastrian (i.e., Jewish, Buddhist, and Christian) ideas.
With the backing of Bahram I, Kartir laid foundations to a Zoroastrian state church.
As a result, Bahram I became applauded in Sasanian-based sources as a "benevolent and worthy king."
His son Bahram II succeeded him as shah; he may have been aided by Kartir to ascend the throne instead of Narseh.
This most likely frustrated Narseh, who had now been neglected from succession several times.
The previous Sasanian shahs had pursued a policy of religious tolerance towards the non-Zoroastrian minorities in the empire. However, with Bahram I's accession to the throne, and the rise of the authority of the Zoroastrian priesthood and the increasing influence of Kartir, this changed; when Mani reached the city of Gundishapur, much uproar occurred, in the same fashion as Jesus' entry into Jerusalem. Kartir, along with other Zoroastrian priests protested and made Bahram I have Mani imprisoned and sentenced to death in 274.
Mani's death was followed by the persecution of his followers by Kartir and the Zoroastrian clergy, who used the persecution of religious minorities as a method to increase and spread their vast influence. Mani was seen by the Zoroastrian clergy as heterogeneous philosopher and a threatening pagan who was presenting an obscure perception of Zoroastrianism, which had been tainted by non-Zoroastrian (i.e., Jewish, Buddhist, and Christian) ideas. With the backing of Bahram I, Kartir laid foundations to a Zoroastrian state church. As a result, Bahram I became applauded in Sasanian-based sources as a "benevolent and worthy king." His son Bahram II succeeded him as shah; he may have been aided by Kartir to ascend the throne instead of Narseh. This most likely frustrated Narseh, who had now been neglected from succession several times.
Kartir