Christianity didn't become the "official" religion of the Byzantine Empire overnight, but rather through a gradual process with key milestones:
* Initial Tolerance and Imperial Patronage: Emperor Constantine the Great, who ruled the Roman Empire (of which the Byzantine Empire was the eastern continuation) from 306 to 337 AD, played a pivotal role. While not making Christianity the official religion outright, he:
* Issued the Edict of Milan in 313 AD, which granted religious tolerance throughout the Roman Empire, ending the persecution of Christians.
* Actively patronized the Christian Church, funding the construction of churches and granting privileges to Christian clergy.
* Convened the Council of Nicaea in 325 AD to address doctrinal disputes within Christianity, asserting imperial authority in religious matters and helping to establish a standardized Christian orthodoxy.
* Gradual Growth in Influence: After Constantine, subsequent emperors continued to support Christianity, contributing to its growing influence in society and government. While paganism persisted, especially among the elite, Christianity steadily gained ground.
* Theodosius I and the Edict of Thessalonica: A defining moment came under Emperor Theodosius I (ruled 379-395 AD). In 380 AD, he issued the Edict of Thessalonica, which declared Nicene Christianity (the version established at the Council of Nicaea) as the state religion of the Roman Empire. This effectively made Christianity the official religion.
* Repression of Paganism: Theodosius I and his successors took steps to suppress paganism, including closing temples, banning pagan sacrifices, and restricting pagan worship. While paganism didn't disappear entirely, its public practice was curtailed, and it lost state support.
* Byzantine Identity: Over time, Christianity became deeply intertwined with the identity of the Byzantine Empire. The emperor was seen as God's representative on earth, and the Church played a significant role in Byzantine society, culture, and politics. Byzantine art, architecture, and law were all heavily influenced by Christian beliefs.
In summary, Christianity's rise to become the official religion of the Byzantine Empire was a process that involved:
1. Tolerance: Ending persecutions.
2. Patronage: Imperial support for the church.
3. Doctrinal Standardization: Imperial involvement in defining Christian doctrine.
4. Legal Declaration: Official recognition as the state religion.
5. Suppression: Limiting alternative faiths.
6. Integration: Becoming central to Byzantine identity.