A. Constantine declared Christianity legal, and it quickly spread throughout the land as Christians were free to worship and were given important leadership positions.
Constantine played a pivotal role in the spread of Christianity throughout the Roman Empire by legalizing the religion with the Edict of Milan in 313 AD. This decree granted religious tolerance and allowed Christians to worship freely. His support for Christianity also included appointing Christians to significant positions within the government and the military, further facilitating the spread of the faith.