Thus Constantine's policies towards pagans can be explained by two arguments. First, the paganism and Christianity of the time were moving towards one another, and this allowed several pagan elements of religion to remain after Constantine converted to Christianity. Second, Constantine needed to solidify his power in Rome and Italy and to legitimize his claims to the throne after he conquered Rome, and the Senate could do both.
After the Battle of the Milvian Bridge, Constantine saw himself as a Christian. After he received a vision and a dream from the Christian God and followed the divine instructions given, Constantine marched into a battle against a numerically superior foe who had the additional advantage of a nearly unassailable city, with the strong walls of Aurelian and stores of food from North Africa. A victory in such circumstances would warrant his conversion, and Constantine's victory caused him to truly favor and venerate the Christian God. This is demonstrated by his favorable attitude towards Christians as expressed in several edicts and letters shortly after the battle. The type of Christianity that he practiced and believed, however, retained several elements of paganism. This fact, combined with his dependency on the Roman Senate to legitimize his claims to the throne, explains the policies of Constantine after the battle. Thus Constantine converted to Christianity after the battle, but it was to his own brand of Christianity --one in which God was a giver of victory, and in which many pagan elements still remained.