I have to disagree with you regarding the first Christians were Roman Catholics, they were not. The first Christians at least most of them never seen Rome, it was Rome, pagans and the Jews who began persecuting the Church beginning in early years of Church, The children of God were first called Christians at Antioch.
The Catholic church began after most all of the apostles died off or were killed off. Then there was a power struggle within all sects of the Church and some leaders in the Catholic sect went in cahoots with Constantine the ruler of Rome and that is when the world began running the Roman Catholic Church. The real church was underground and it was called the Universal Church "catholic" meaning universal. The apostles had warned about the ravenous wolves about to devour the flock, and Rome did just that, if you have not read " Foxes book of Martyrs, you should, it tells of all the atrocities of the roman catholic church in detail . Please do not misunderstand me, I believe there are good people in the Catholic Church, but they are being deceived!