Christianity as the State Religion of the Roman Empire
Christianity became the state religion of the Roman Empire in the 4th century. This significant event occurred during the reign of Emperor Constantine the Great in the early 4th century.

Conversion of Constantine
- Constantine, after experiencing a vision of a cross before a decisive battle, embraced Christianity and attributed his victory to the Christian God.
- In 313 AD, Constantine issued the Edict of Milan, granting religious tolerance to Christians and effectively legalizing their faith.

Edict of Thessalonica
- In 380 AD, Emperor Theodosius I issued the Edict of Thessalonica, also known as the "Cunctos populos" decree, declaring Christianity as the official state religion of the Roman Empire.
- This decree marked the culmination of Christianity's journey from a persecuted minority to the dominant religion in the empire.

Impact on Christianity
- The official recognition of Christianity as the state religion brought about a significant shift in the status and influence of the Church.
- Churches were built, Christian practices were incorporated into state ceremonies, and the clergy gained more prominence in society.
- The state-sponsored conversion of the population to Christianity led to the widespread adoption of the faith throughout the empire.

Legacy
- The establishment of Christianity as the state religion of the Roman Empire had profound and lasting effects on the course of Western civilization.
- It shaped the development of art, architecture, law, and culture in the medieval and modern periods.