Stephen Beale, Catholic Exchange: After Constantine the Great, there were emperors who were heretics and emperors who adhered to Christian orthodoxy.
Then there was Julian the Apostate.
From the time of Constantine to the French Revolution, he is the only Christian monarch ever to openly reject the faith, according to Catholic historian Warren Carroll. For reasons both personal and intellectual, Julian launched the last great attempt to revive ancient Roman paganism. Animal sacrifices resumed in the reopened pagan temples while the Church was stripped of the imperial funds and lands that had been granted under past emperors. Read story here.