Answer:
Constantine adopted Christianity as his religion and, by extension, as the religion of the Roman Empire. At that point, monotheism, in its Christian form, for the first time became a bandwagon. Down until the time of Constantine, you had to be pretty strongly interested in your eternal salvation for it to make sense to convert to Christianity. After Constantine, people like you and me are jumping on the bandwagon. Well, I shouldn’t speak for you, but people like me are jumping on the bandwagon. It makes excellent sense in this world to convert to Christianity.