I did not say anything about non-Catholics posting. What sometimes happens is that it becomes impossible to discuss complex issues involving Catholicism when non-Catholics begin trolling about the basics: "why Mary, why papacy, why icons, etc...". I did not see any trolling on this thread at all, certainly not from you. It is great that non-Catholic participate, criticize and question as long as it does not become yet another brawl that never lifts above fundamentals of Catholicism superficially discussed.
To answer your question, prior to 11 century the Church was free from schism (there were various heresies but no schismatic denominations). It was a single, united Church that was at the same time Catholic and Orthodox. The term "Roman" refers not to Catholicism but to the Latin rite inside Catholicism; it does not attach to the Eastern Fathers, such as St John Damascene. But St. John is Catholic as well as Orthodox.