When did Constantine make Christianity the state religion of the Roman Empire?

Answer 1

Strictly speaking, Constantine did not make Christianity the state religion of Rome - this did not happen until 391 CE, some sixty years after his death.

However, Constantine did set in place the process by which Christianity would inevitably become the state religion. He gave Christianity state patronage and massive financial support, began the persecution of pagans, and stripped the pagan temples of their treasures, humiliating them in the eyes of the faithful. Nevertheless, at the time of his death, the majority of the population had remained faithful to the pagan gods and paganism remained nominally the state religion, or at least on an equal basis with Christianity.

Answer 2

Emperor Theodosius made Christianity the state religion of Rome in the 380s.

Christianity still had too small a proportion of the population to officially be made the state religion during Constantine's reign.

Answer 3

Emperor Theodosius made Christianity the official religion of the Roman Empire in 381 and then banned the public worship of the pagan gods in 391, so this could be considered the date on which Rome changed from paganism to Christianity. However, the majority of the Roman Empire was still pagan and remained so for some time to come. However the majority of the population of Rome itself was probably more Christian prior to the year 391.

Answer 4

Christianity became the official religion of the Roman empire by order of Theodosius I in the year 380 when he ordered mandatory Christianity for everyone.