Everlast 3

Roman shield with Chi Rho

Anyway, just before a battle Constantine had a vision of the Christian symbol, Chi Rho, which convinced him the Christian God was on his side. His resulting victory in what was thought a hopeless battle inspired Constantine to lift the persecutions of Christians. And he would spend an enormous effort for the remainder of his rein in supporting and spreading the faith.

Skip about 500 years to the end of the Dark Ages and we get Charlemagne. He was a conquering emperor—he was French, so go figure. Known then as Charles I, Charlemagne managed to unite much of Europe. In doing so, and as a good Medieval Christian (a somewhat disreputable time for the faith), he forced the Christianization of the Saxons, the Danes, and the Slavs, while banning their native paganism under threat of painful death. Charlemagne integrated all these people into his empire, while simultaneously integrating select pagan traditions into Christianity. This had the effect of easing brand acceptance by utilizing certain advantageous elements to further spread the faith.