Christianity was a religious minority in the Persian Sasanian Empire, roughly the region of modern-day Iraq and Iran from 224 to 651 CE. Christianity had been introduced into the Persian world earlier, in the second century during the Parthian period (before the Sasanians), likely spreading into Iran through the eastern border of the Roman Empire. Beyond this, little else is known about the origins and early history of Persian Christianity. In the Sasanian world, Christianity was often persecuted in the context of its tensions with Zoroastrianism, which had become the state religion of the Sasanian Empire in the third century, and sometimes in fear that Christians would collude with their main political rival, the Roman Empire, whose conversion to Christianity began with the reign of Constantine the Great in the early fourth century. The most intense persecution is believed to have occurred in the reign of Shapur II, with accounts describing the deaths of up to 16,000 Christians. Persecutions continued to take place over the centuries, in the reigns of Shapur II, Yazdegerd I, Bahram V, Yazdegerd II, and others, which came to be popularly expressed in Christian memory through the Persian martyr acts, or narrative accounts of the martyrs of Christian men and women who confessed their faith or converted to Christianity from Zoroastrianism in the face of death. At the same time, beginning in the fifth century, a growing trend of normalization took place between Christians and the empire.
Despite the periods of persecution, Christianity grew throughout the Sasanian world and bishoprics formed in all major cities under the ecclesiastical organization of the Church of the East. By recognizing the Eastern churches' full independence (institutionally and hierarchically) from the churches in the Roman world, some Persian rulers sought to foster a local Christianity free from the influence of their Roman rivals. Relatedly, Christianity in the Sasanian Empire diverged from Chalcedonian Christianity, often being expressed through Nestorian and Monophysite doctrines. The only region whose Christians were predominantly Chalcedonian was Iberia.
There is a wide range of opinions regarding the extent to which different religions in the Sasanian Empire coexisted harmoniously. The prevailing view today is that persecutions of Christians were more the exception than the rule and that they occurred for political reasons, both external and internal.
Period
Parthian period
The era in the Iranian history between the Avestan and Sasanian periods, when from the late 4th century BCE to the early 3rd century CE was characterized by religious diversity. During this time, Iran was under the rule of the Parthian Arsacid dynasty. The traditional Zoroastrian tradition began to fade, giving way to the worship of various spirit-daevas. During this time, Jewish and Christian communities also emerged in Iran. Ruled by a junior branch of the Arsacids, Armenia by 190 BCE was a conglomerate of 120 principalities governed by nakharars, some of which adhered to Persian cults, while others followed Hellenistic practices. According to James R. Russell, the subsequent Artaxiad dynasty (189 BCE – 12 CE) supported Zoroastrianism. Generally, the prevailing view is that the state adhered to principles of religious tolerance or was indifferent to dogmatic issues during the Arsacid period.
The moment of the Christians in Mesopotamia appearance is unknown and remains a subject of debate. French archaeologist Jean Maurice Fiey (1967) dates the event to the late 1st century, while American historian W. S. McCullough (1982) suggests it occurred a century later. According to the renowned Syriac researcher Sebastian Brock, Christian communities, isolated from the church of the Roman Empire, could have existed in Mesopotamia from the 2nd century. The desire to attribute antiquity to their church led, for example, to the late 8th-century Nestorian patriarch Timothy I claiming that "Christianity among us was founded approximately before Nestorius and twenty years after the ascension of our Savior". Most likely, Christianity reached Persian territory via trade routes from Edessa, appearing first in Nisibis, Arbil, and Veh-Ardashir.
The spread of Christianity from Edessa further east is mentioned in the Acts of Mar Mari, dated tentatively to the early 7th century. The task of the authors of the Acts, living in the 6th to early 7th centuries, was to substantiate the antiquity of the Church of the East in the territory of modern Iraq and the authority of its catholicoses, whose residence was in the Sasanian capital Veh-Ardashir, also known as Kokhe and Seleucia-Ctesiphon. According to the Acts, from Edessa, Mari traveled toward Nisibis, then through Adiabene south to Babylonia. Upon reaching Kokhe, he founded the first church there.
After converting Babylonia to Christianity, Mari proceeded to Persia, starting with Beth-Huzaye and Elam in southwestern modern Iran. The Acts claim that through countless miracles, Mari established a widespread church hierarchy in Persia, with numerous priests, deacons, schools, teachers, and hospitals. Most likely, the Christian centers described in this apocryphal text were established closer to the time of the document's composition than to apostolic times.
Another source, the 6th-century Syriac Chronicle of Arbela, names Mar Pkidha as the first bishop of Adiabene. According to the chronicle, by the time of the fall of the Parthian Empire, there were 20 Christian bishops in Mesopotamia. Church tradition links the emergence of Christian communities in the East with the activities of the apostles Peter, considered the first patriarch of the Eastern church, and Thomas, as well as the apostle of the Seventy Thaddeus (Addai) and his disciple, the apostle of Mesopotamia Mari, through whose efforts the church became known as the "church of Mar Mari".
An idealized version of the history of Christianity's emergence in the capital of Osroene, Edessa, is presented in the Doctrine of Addai, dated to the first half of the 5th century. The correspondence between King Abgar and Jesus Christ cited there has led some researchers to consider Osroene the first country to adopt Christianity. There are also grounds to suggest Antioch or Palestine as sources of Christianity in Edessa. In modern historiography, the earliest Christian communities in Parthia are identified among Jews who had lived there since the Babylonian captivity. According to one hypothesis, Christianity spread eastward with trade caravans, with Jews controlling the routes through the Persian Gulf to Central Asia and China.
Although information about beliefs in early Christian Osroene is limited, sources suggest the presence in Edessa of various religious groups, including Jews, adherents of traditional forms of Greco-Roman and Aramaic polytheism, and Manichaeism. Religious diversity in Edessa was facilitated by its geographic location at the border of the major empires of the ancient world and at the crossroads of trade routes. German historian Walter Bauer describes Christianity in Edessa as "heretical" and consistently distant from orthodoxy. Zoroastrian Parthians showed no hostility toward the Christian and Jewish minorities, in contrast to the Roman Empire, where Christians faced systematic persecution. Due to the absence or minimal presence of persecution, the cult of martyrdom spread in the East only in the 4th century.
Early Sasanian period
In 224 CE, Ardashir I (224–241), the founder of the Sasanian dynasty, came to power in Iran. According to available information, his family had close ties with the Zoroastrian clergy. The 6th-century pseudepigraph Letter of Tansar justifies the legitimacy of the dynasty's rise to power through its religious zeal, positioning Ardashir as the true heir of the ancient Achaemenids.Not all researchers, particularly I. M. Diakonov, recognize the Achaemenids as consistent Zoroastrians. The anonymous author criticizes the apostate Arsacids and their policy of religious tolerance. Under the early Sasanians, the clergy (mobeds), led by the magupat (chief of the magi) or, later, the mobedan-mobed, assumed a prominent position in society.
During the reign of Shahanshah Bahram II (276–293) and the active efforts of the Zoroastrian priest Kartir, Zoroastrianism became the state religion for the first time in Iranian history. Kartir's inscriptions and his threats against non-believers are the subject of numerous studies attempting to determine the extent of religious intolerance among Zoroastrian mobeds. Despite the threatening rhetoric, there is no confirmation in Christian, Jewish, or Mandaean sources that persecutions took place. The only exception is Manichaeism, whose prophet Mani was executed under Kartir. According to British Iranologist Mary Boyce, the Sasanian period alternated between phases of religious tolerance and intolerance, with Kartir's activities falling into the latter category. Soviet Orientalist Elena Doroshchenko considers intolerance a defining feature of Sasanian Zoroastrianism. Several later researchers have criticized this binary opposition as oversimplified. They have found evidence in late Sasanian texts of more nuanced interactions between state Zoroastrianism and religious minorities in the early period. It has also been suggested that relations between the state and mobeds were significantly more antagonistic than depicted in Zoroastrian sources.
Traditional historiography describes the relationship between Zoroastrianism and other religions in the Sasanian Empire using terms such as "state religion," "church," and "persecution." This view considers secular authorities' interference in citizens' spiritual lives as a form of persecution. However, Professor Adam Becker of New York University argues that this terminology is an anachronistic legacy of the liberal ideas of the European Enlightenment, employed due to a lack of better analogies.
In the Middle Persian language, all non-Zoroastrian religions were designated by the term agdēn ("infidels," see also agdēnīh – "bad religion"), considered synonymous with the term anēr, Aneran, non-Iran. In this ethnolinguistic concept, Christians also identified themselves as part of Aneran, which was preferable in legal terms to being considered apostate Zoroastrians. Jews and Manichaeans held the same position. Sources for studying Sasanian law include various collections of precedents, such as the Madigan-i Hazar Datistan.
Christian hagiographic literature can also serve as an additional source, though the accuracy of the legal procedures described therein is questionable. After Zoroastrianism was established as the state religion, the legal system became Zoroastrian in character and restricted the rights of religious minorities. Although Zoroastrian law applied to all subjects of the shah, a personal principle was also in effect, whereby each individual was subject to the law corresponding to their status. In trials against Christians, the prosecution was represented by mobeds.
In Sasanian culture, the purpose of punishment was to save the offender's soul from the consequences of their crime. The first, but not the only, condition for saving the sinner's soul from posthumous retribution was an honest and complete confession of sins. In the case of Christians, the state and religion were considered the injured parties in judicial proceedings, and the process was inquisitorial. The aim of measures applied to the accused, including arrest and torture, was to convince the heretic of the error of their beliefs and the truth of Zoroastrianism. Being born Christian was not considered apostasy. Christians were not prohibited from serving in the Sasanian army, where they could hold high positions. Nevertheless, sources indicate that the loyalty of Christians to the shah persisted until the 7th century.