lol, ya know they say that if you want to know the truth, look to the heretics, but that does not hold water. At that time Gnosticism was on the rise and the church of Alexandria was gaining strength. Constantine chose the religious beliefs of the Christians in Rome and the seven churches of Asia Minor. If he had not, Christianity as we know it may not have survived. He was the one that ordered the Christian manuscripts to be preserved and bound in the first Bibles. So if that had not happened, it would have been the Gnostic texts that were preserved and our Bibles today may have been written by Gnostics. In that era preserving texts was a costly affair. Protecting them took power.
We tend to look back on history with a critical eye, not understanding that the culture of the period was nearly alien to anything we could imagine. The Flavian Amphitheatre and other arenas are a standing testament to the time period. It was not just the empires that were cruel and violent. These arenas were the entertainment of the period. Christians and others were herded into these and crowds clapped and yelled in approval as the most horrible things were done to them. Then you also had gladiator tournaments and other forms of violent entertainment. This would be like a stadium of football fans cheering on their perspective teams. It was not just the empire, the populace was cruel and violent. Those crucified with Christ were thieves. If you entered a large Roman city you were likely to walk past those that had been crucified and stood as a warning to those entering the city.
This is the atmosphere that early Christianity evolved in. Constant fear and persecutions that lasted for centuries. Since it was the norm, it affected Christianity. Suffering became a testimonial to Christ, who suffered and it continues on to this day. In the Middle Ages you had groups called Flagellants who whipped themselves and each other. In Mexico and South America people allow themselves to be crucified and stigmata has deep religious significance. Catholic clergy practicing what is called self mortification in different forms. Again it was a cultural thing, but even today, Catholic and Protestants see suffering as having a religious context.
It does not take a deep study of ancient history to see a cultural lust for world domination in all of the empires, one after another. This was the norm, and the Catholic Church adopted it, not as much as the church was evil, but it was the cultural mind set. So then since the Church had the ear of the Roman Empire so they got into the desire of belief control and domination. From there, the Church was in bed with whatever empire ruled. Sound all horrible and by our standards it was, but only because we do not understand the cultural environment. We know that slavery is bad, back then, it was the norm and Christ spoke of it. In the beginning, Christianity was the religion of the slaves.
Still condemning the Catholic Church for past sins is very short sighted. There is no reality in attempting to deny that the Catholic Church was Christ's Church on earth, during this time period. The Protestants came into being during the Renaissance Era, a time when society was intellectually removing themselves from the desire for world domination and cruelty, even though the the desire continued on with Neapolitan and Britain. But still the history within the Protestant ranks was not always peaceful. It wiser to learn from history than to condemn it. More Christian to forgive, than to hold a grudge.