Lets look at just how much the Followers of the Way increased in membership during the Pre-Constantine years. Here is what Wikipedia says about that:
Early Christianity spread from city to city throughout the Hellenized Roman Empire and beyond into East Africa and South Asia. The Christian Apostles, said to have dispersed from Jerusalem, traveled extensively and established communities in major cities and regions throughout the Empire. The original church communities were founded in northern Africa, Asia Minor, Armenia, Arabia, Greece, and other places by apostles (see Apostolic see) and other Christian soldiers, merchants, and preachers. Over forty were established by the year 100, many in Asia Minor, such as the seven churches of Asia. By the end of the 1st century, Christianity had spread to Greece and Italy, even India. In 301 AD, the Kingdom of Armenia became the first state to declare Christianity as its official religion, following the conversion of the Royal House of the Arsacids in Armenia. Despite sometimes intense persecutions, the Christian religion continued its spread throughout the Mediterranean Basin.
As you can see there was rapid growth during the early years. Some today believe that before Constantine made Christianity a State religion where membership was mandatory that the church was struggling to grow. This was just not the case. In three hundred years they had basically spread throughout the known world. Yes, when Christianity was made mandatory it grew but its new members just didn’t have the compassion in either faith or practice of the earlier followers. Nothing mandatory is ever approached with the same zeal as when it is a choice. And, of course, being a mandated state religion also brought power and money which would inevitably lead to corrupting influences among some of the church leaders.
What would have been the alternative path of Christianity had Constantine not used it to try and shore up his crumbling empire? Of course we can only speculate about that but I personally believe that Christianity just might have been much stronger without his interference.
But that is a matter for another post….