Explanation: The Roman Emperor Julian the Apostate was the last pagan Emperor of Rome, coming after a string of Christian sons of Constantine, the first Christian Emperor. One of his actions was to repeal the oppressive edicts of the Christian Emperors which condemned other faiths, instead declaring tolerance for all religions in the Empire; Jewish, Christian, Pagan, Zoroastrian; all.
The Christians, who had long pled when they were not the dominating religion that they only wanted to live without interference from the Empire, were incredibly pissed at this. Perhaps worse, this included tolerance for Christian sects, whereas one of the big movements in the Christian Church at the time was "How many heretics can we get the Empire to execute for the TRUEST strain of the TRUE FAITH".
What a tyrant Julian was!