And not until Constantine that all authority was centralized in Rome.
You're so right. I think when the power of the state began to be used to enforce the will of a centralized religious authority is when the separation from Biblical Christianity was completed.
It's sad how there is a never ending effort to rewrite history. Peter is always being proclaimed as the first pope/bishop of Rome. I don't doubt that he was crucified in Rome by Nero, but there is no evidence in Scripture of Peter residing in Rome and being "bishop" over this church.
In Luke we are told that Peter's apostolic activity takes place in Samaria (8:14), Lydda (9:32-35), Joppa (9:36-43) and Caesarea (ch. 10). Pg 29, From Apostles to Bishops by Francis Sullivan
Once the lies start they can never be denied. Examples like this make it easy to understand why the RCC has a three legged stool of tradition, magisterium and Scripture rather than Scripture Alone as the rule of their faith. They can always fall back on their unwritten tradition to support a lie.