WORLD HISTORY

Detailed explanation-1: -Emperor Constantine himself became Christian, and Christianity was made the official religion of the Empire.

Detailed explanation-2: -Christianity became the official religion of the Roman Empire when Emperor Theodosius I issued the Edict of Thessalonica in 380, which recognized the catholic orthodoxy of Nicene Christians in the Great Church as the Roman Empire’s state religion.

Detailed explanation-3: -Not too long after, in 380 CE, the emperor Theodosius signed the Edict of Thessalonica, making Nicene Christianity the official religion of the state, which confirmed and solidified the influence of Christianity not only on the Roman world at the time but also for the rest of world history.

Detailed explanation-4: -Theodosius was a strong adherent of the Christian doctrine of consubstantiality and an opponent of Arianism. He convened a council of bishops at Constantinople in 381, which confirmed the former as orthodoxy and the latter as a heresy.