Sure, the 313 AD Edict of Milan is often cited as an ancient model of religious tolerance.
Indeed, had that model been followed consistently up to our current time, the world would likely have been a different place.
But it was not, and though large-scale persecutions of non-orthodox Christians did not begin for some time, it's foundations were laid by the Emperor Constantine at the Council of Nicaea, in 325 AD.
So, we can say, the Roman Empire's first experiment with religious freedom lasted all of twelve years.
Already at the Council of Nicaea, heterodox Christians -- especially Arians -- were condemned to death by decree of Constantine.
At the time, that affected only a few, but it was a beginning.
RobbyS: "I was speaking of the situation before the Diocletian persecution, which itself was the climax of more than 50 years of “hard times” for the Christians.
This is far more relevant to the question of the influence of the Jews on the Christians of Antioch than any discussion of persecution after the Establishment of Catholicism as the state Church under Theodosius. "
You didn't somehow forget, did you, that Jesus was Jewish, so were his original followers, and so were many who later called themselves "Christians" in places like Antioch?
You didn't ignore that ideas of being both Jewish and Christian were considered a punishable "heresy" only by those first elevated to power by Emperor Constantine, right?
RobbyS: "The situation of the Church of Rome, as the Latin patriarchy, was pretty bleak in 500, with the only bright spot being the conversion of the Frankish king and his court about that time.
There was a dark side, all right, and Church persecution of others had little to do with it."
There is a long dark history of Christian sponsored persecutions of heretics, pagans, Jews and others who refused to submit to Catholic doctrines.
It all began with the Emperor Constantine at the Council of Nicaea, when the spirit of toleration seen in the Edict of Milan was first overthrown.
The Edict of Milan aimed to empower Christians, not to establish religious toleration as we understand it. It was a political act, which sought to strengthen the Emperors hand. He intervened to strengthen the orthodox party in the Christian Church, and even before he dealt with the Arian issue, dealt with the Donatists. It was the divisions in the church more than the secular power that was at the root of the matter. It was their divisions, their lack of unity that prompted them to let Caesar decide. It was the same thing that recurred in the 16th century, in what is called the Reformation, but which was in fact a bloody war between Christians, that played into the hands of princes, and in the end, caused such slaughter that Christianity was discredited in the eyes of reasonable men. What a difference an iota in a creed can make can make, or as the Jews discovered once upon a time, the taking of one man’s life can cause fountains of human blood to flow.