Tom Woods talks about Constantine's ruleship, and after the battle of the Milvian Bridge. Constantine was baptized soon before he died. Some people speculated as to why he was baptized so late, and during those times it was customary to get baptized as late as possible, since they believed once you get baptized, then all the sins before that point were forgiven.
During Constantine's ruleship, he implemented new laws to protect the Christians. He abolished the crucifixion of Christians, and he made Sunday a holiday.
He also removed gladiator games, which was a game where 2 people, often convicts, would fight to the death for entertainment. Constantine also improved the living conditions for women and slaves, which at the time it was legal to beat women and slaves under your household.
Sacrilege to the Christian faith was also made a crime. Much of society at the time started discouraging other practiced pagan religions.