I have been doing some very interesting studies about the origions of the early churches. I read of Paulenes of the eastern orthodox Churchs, and the origional Coptic Christians in Egypt and Jordan. Also the Western Church which was eventually was the Roman Church. All catholic as in the "universal sense" as well as Catholic in the Church beliefs. They did have some differences, and these did cause many dissents over the centuries. It is facinating to try to learn and distinguish all these differences, why there were differences and what they were about.
I found the JW beliefs are aryan, which in the early centuries were considered heritic becaue they did not believe in the divinity of Jesus Christ.
Then th great reformation which came about with the former Catholic Martian Luther and it was boiling down to salvation by faith lone ( Luthers belief) , vs salvation by works along with faith, from which prodtestantism found its birth.
I am only just beginning these studies, so I have a lot to learn but it is facinating.