I am continually amazed with how rapidly the Christian faith grew in its early stages. The impact of Messiah was so dramatic that by 312 AD, the emperor embraces the Christian message. As my former professor Frank James summarizes:
By the middle of 2nd century, we know that Christian churches existed in most of the Roman provinces from Syria to Rome. In 250AD, we know that a significant minority of Christians existed in every Roman province. By 300AD, Christians in some regions (North Africa and Turkey) represented a majority of the population. In 312, Constantine embraced Christianity.