Rome's adoption of Christianity

The first Christian country?

The legendary visit of the Persian Magi to Bethlehem (Matthew 2. 1) does not appear to have led to immediate further contact between Persia and the first Christians.

For the spurious claim of Abgar V of Edessa (Osrhoene) to have been the first Christian king see here. Tiridates III of Armenia may have a slightly better claim, but the main source is so full of nonsense it's hard to be entirely convinced - see here. But it was the Edict of Milan in AD 313, which permanently established religious toleration within the Roman empire, as a result of an agreement between Constantine and his pagan ally Licinius; both attempting a moral blackmail of their rival emperor Maximin, who was still allowing Christians to be abused. The Edict of Milan allowed freedom of worship: the Roman empire did not adopt Christianity as its official religion until the Edict of Thessalonica in AD 380.

Constantine the Great

The emperor Constantine

Shapur sent gifts to Constantine and suggested an alliance. Constantine wrote back that he'd heard there were many churches in Persia with large congregations, and had this suggestion:

Concerning this category of people - Christians I mean (that's who this letter is all about), how delighted do you think I am to discover that - just as I'd have wanted - the lovely land of Persia is a showcase for them? May you bring them as much blessing as they bring you. You will find the Lord of All gentle, kind and sympathetic. And so I hand them over to you, powerful as you are and famous for your piety, to look after. Love them in accordance with your love for humanity. Through this act of faith, you will be doing a great service to yourself and to me.Eusebius of Caesarea, Life of Constantine

How do you imagine Shapur II reacted?

The adoption of Christianity as the state religion of the Roman empire had a an unexpected effect on the Christian communities in the Sasanian empire. Persecution stopped within the Roman area (where it had been widespread before), but began in the Persian empire (where religious tolerance had been normal since the days of the Achaemenids, and where many refugees from Roman persecution had come for safety). Another irony was that Shapur I, who'd wanted to promote the Mazdaean religion and associate it with Eranshahr (ie with "being an Iranian") had imported many thousands of Christians - as prisoners of war and deportees from Syria.

Spread of Christianity in the Persian empire

First Christian communities

There were probably small numbers of Christians arriving along trade routes from the west in the 2nd and 3rd centuries AD, but the main influx is usually dated to Shapur I's deportations. Christianity, too, easily found a home within the already large Jewish community in Iraq. Archaeology has revealed evidence of Christianity in the 3rd century from Kharg island in the Persian Gulf (60 tombs - which may have been of martyred victims of Kerdir), and Dura Europos. Kerdir's boasts of persecuting Christians along with Jews, Manichaeans and Buddhists suggest that there was already a significant presence in the second half of the 3rd century.

The Church of the East

Gradually, the Christian communities scattered in cities throughout Iran (though especially in Mesopotamia) got themselves organised: in AD 315 a bad-tempered meeting of leaders ended with recognition of the bishop of Seleuceia-Ctesiphon as head of the "Church of the East" (which is its official name today). But Shapur II was not pleased when the newly appointed Christian leader refused to collect a special tax which he'd imposed on Christians in Mesopotamia. They'd refused to help in the siege of Nisibis - and the tax was a punishment:

We are in a state of war; they are in a state of joy and pleasure. They live in our land but are of like mind with the emperor, our enemy.

Bishop Shimun replied:

We will not agree to to collect taxes so that we may murder our brothers.

Shapur II (according to Christian writings) offered Shimun the opportunity to renounce his beliefs and worship the sun and fire: when he went on refusing, Shapur arrested 100 priests and had them beheaded in front of him, before Shimun was executed himself. There followed wholesale denunciation and slaughter of Christians throughout Persia, many of whom willingly accepted torture and death - by a variety of original and sadistic methods, according to the Syriac Christian Acts of the Martyrs. The persecution was sanctioned by Shapur II and carried out by the the Magi.

Christian victims

The Magi, as well as regarding Christianity as un-Iranian, disapproved of the Christians' mission to convert Mazdaeans to their religion. For the next 50 years those Christians who survived understandably kept a low profile, though there is archaeological evidence that there was less persecution in the east. Merv had a bishop, and remains of a church, monastery and Christian burials have been found dating from this period.

Eastern Christian beliefs

The Church of the East (sometimes called the Assyrian church and - inaccurately - Nestorian) had since earliest times been cut off from the western branches of Christianity by the Euphrates frontier with the Roman empire. It took no part in the great church pow-wow at Chalcedon in AD 451 where quarrels were settled, and what you had to believe to be a Christian was (to some extent) stabilised.

Assyrian church in Yonkers

The Church of the East was free to continue in its own way. It avoided the Manichaean influence of Augustine which convinced the Orthodox church that man was naturally evil, as a result of the "original sin" of Adam. For the eastern Christians, man was basically good - although he could still choose to do evil. The emphasis was on the humanity of Christ. There was none of the Orthodox obsession with suffering. Their cross was not originally a symbol of the crucifixion, but an ancient symbol of the sun, source of all life (as found in Elamite carvings from 4000 BC). In AD 424 it proclaimed its complete independence from Orthodox Christianity - who of course immediately condemned it as heretical. There were also other Christian sects within the Sasanian empire - there were Jacobites, or Syrian Orthodox, for example, and Melkites.

Tombstone of Elizabeth in China

Tombstone of Elizabeth, Christian wife of a Chinese official 14th century AD

It was much easier after that for Christians in Persia to be accepted - because they were also enemies of the Orthodox emperor in Constantinople. Eastern missionaries took Christianity to India, Tibet and China along the Silk Route; the Church of the East was bigger than the Roman Catholic church until the 16th century (when forcible conversion of "heathens" in the New World began to boost its numbers). In AD 522, an Egyptian monk reported Christian churches and communities, and a bishop consecrated in Persia, in his travels along the south west coast of India as far as Sri Lanka (Taprobane). And this without ever being sponsored by a government, or using any means other than persuasion to promote their beliefs. By AD 400 the Church of the East was fully recognised by the Sasanians, with its patriarch resident in Ctesiphon. Its first synod was convened in AD 410, during the reign of the "friendly and peaceable" Yazdegird I, followed by 10 more synods up until AD 775.

In 1281 a Mongol was elected to the office of Catholicos: supreme patriarch of the Church of the East.

Other religions under the Sasanians

Manichaeans were banned, not just persecuted. Buddhists were persecuted, like Christians. Jews were generally tolerated, though - and king Yazdegird I was said to have married a Jewish woman, Susannah. Bahram V (if he was her son) would therefore himself have been Jewish. The Jews, through their Bible, had knowledge of the Achaemenids - and particularly of Cyrus and could remind the Persians of his generosity to Judaean captives in Babylon. Jewish academies in Mesopotamia produced the Talmud during the Sasanian period. By around AD 400, during the reign of Yazdegird I, a Jewish exilarch, as well as a Christian bishop resided in Ctesiphon: they paid their taxes, and enjoyed security in return.

Mazdaism: becoming a church?

After the energetic promotion of Mazdaean religion by the priest Kerdir, this question seemed to expect the answer yes. But in fact it was still no. Individual kings could show greater or lesser enthusiasm. State and religion supported each other - but Mazdaism/Zoroastrianism was never the "state religion" (as Christianity became in Byzantium). Nevertheless, Mazdaean priests became more powerful, and fire temples became wealthy and important. Christians, Manichaeans, Buddhists and even Jews were persecuted from time to time - but always for political reasons (although the Magi would have had strong religious reasons for approving of attacks on rival religions). Persecution of Christians always reflected current relations with Constantinople. By the sixth century, Christians were probably in the majority, at least in Iraq.

Stung by criticism from Manichaeans that they had no "book", the collection of writings (begun under the Parthian Valaksh I) that became the Avesta was continuing, though not completed for another two centuries. It's worth noting that there is no mention yet of Zarathushtra or Zoroaster by the Sasanians - they're still really Mazdaeans rather than "orthodox" Zoroastrians. At the same time, Anahita and Mithra were becoming more important, and more closely associated with Ahura Mazda.

Just as Christians were growing in number within Eranshahr, so smaller numbers of Mazdaeans were spreading westward into Anatolia. In Armenia, despite its ruler's conversion to Christianity, there was still a significant Mazdaean presence.

Christianity v Mazda-worship

Each community had reasons for disapproving of the other: Christian sexual obsessions (virginity; celibacy) shocked Mazdaeans who were happy to marry their sisters (and vice versa).

See here for a table highlighting the main differences and similarities:

Christianity v Mazdaism


(has to be mentioned)

The men-only cult of Mithras, though taking its name from Mithra, the Iranian deity, seems to me to have no serious connection with Mazdaism or any Persian religion. It was extremely popular in the Roman army, and its underground chapels have been found all over the Roman empire. I would compare it to cults like Scientology in the modern world - an invented religion using familiar and exotic elements taken from the substrate of popular religions (eg, like Christianity it has a virgin birth, shepherds, baptism, communion and Satan). Its inventor/s - probably somewhere between 50 BC and AD 50 - were familiar with Indian scriptures and Greek philosophy - especially Plato's Timaeus. The earliest Roman inscription referring to Mithras is from AD 194. No Mithraeum has been found in Persia, "and probably never will be" - the nearest was in the Roman garrison town of Dura-Europos. More on Mithraism here


Remains of a Mithraeum at Carrawburgh, near Hadrian's Wall