Christianity in Sassanian
Persia

Fire Altar from the reign of Ardashir
Shapur (II, ) built the city of Karka d-Ladan, brought captives from various places and settled them there. He also had the idea of bringing about thirty families apiece from each of the ethnic groups living in the cities belonging to his realm, and settling them among the deported captives, so that through intermarriage the latter should become tied down by the bonds of family and affection, thus making it less easy for them to slip away gradually in flight and return to the areas from which they had been deported. Such was Shapur's crafty plan, but God in His mercy turned it to good use, for thanks to intermarriage between the deported population and the native pagans, the latter were brought to knowledge of the faith.
from the Acts of Pusai
Pusai: Far be it from a servant of the living God to consider you to be despicable and contemptible, O mighty king. Father, he considers you to be a mighty king, a renowned king, the shahanshah (king of kings).
Shapur (II): How can you consider me to be so, as you claim to, seeing that you have the audacity to swear in my presence by God, and not by the gods?
Pusai: I swore by God because I am a Christian; I did not swear by the gods because I am not a pagan.
Shapur: How can you consider me to be shahanshah, mighty and powerful, when you have had the effrontery to say in my presence that you are a Christian?
from the Acts of Pusai
It is right that in all the churches of this exalted and glorious kingdom that our lord the victorious Khusrau, shahanshah (king of kings), be named in the litanies during the liturgy. No metropolitan or bishop has any authority to waive this canon in any of the churches of his diocese and jurisdiction.
Synod of 576, Canon 14
Now King Khusrau (II, reigned 590-628) the son of Hormizd reigned in the nine hundred and first year, according to the reckoning of the Greeks, and he lived in his kingdom thirty-eight years. In the fifth year (595) then, of Khusrau according to what is written by the holy Rabban Isho-zekha, who lived in the days of the last Mar Isho-yahbh, who built the new temple (church), the coming of Rabban Joseph to this Monastery took place. And I, myself, having carefully investigated the matter of the date, have found from the history of Rabban Bar`Idta that the time of his coming was exactly according to the word of the holy Rabban Isho-zekha.
Now when King Khusrau wished to build a convent in honor of Shirin his wife, in the country of Beleshphar (a town in Adiabene), he sent to the city of Edessa, to the good man of worthy memory, Shamta, the son of the blessed Mar Yazdin (a powerful and wealthy Nestorian noble), telling him to bring from there copies of the Holy Scriptures, and Prayer Books, and Lectionaries, which were to belong to that convent. And after he had gone there, and finished his business, he brought with him for Rabban a large Service book, and he asked for Rabban's prayers and set out for his own country. And all the books which Raban wrote with his own hands, were copied from the service book which the honorable Shamta brought to him, and in the greater number of them may be found written this, "Mar Shamta, the son of Yazdin, the prince of believers, gave this service book."
Thomas of Marga, The Book of Governors, 1.23