How come there are only a few Roman Catholic nations within the classical Roman Juris

Roman Catholic Nations within the classical Roman Jurisdiction:
Spain, Portugal, Belgium, France, Italy, Croatia, Austria, Malta, Slovenia, Luxembourg, Leichenstein.

Non-Roman Catholic Nations within the classical Roman Jurisdiction:
Israel-Palestine, Britain, Turkey, Greece, Egypt, parts of Sudan, Libya, Tunisia, Algeria, Morocco, Syria, Bulgaria, Romania, Lebanon, Jordan, Macedonia, Serbia, Bosnia & Herzegovina, Albania, Montenegro, Hungary, Netherlands, Armenia, & parts of Iraq.
I'm writing a paper.

because everyone is now free to discover the truth on the evidence as they see it.

You don't remember that whole thing when the Roman Empire split in two (Roman Empire and Byzantine Empire)? Most of those countries were under Byzantine Rule.

As for the UK, the King wanted a divorce, and the pope said no, so they went off on their own little thing.

And then there was that whole Muslim conquest of Arabia and Africa thing.

Albania was one of the first nations in EU to become Catholic, the whole country was also with Roman Jurisdiction. But in the Balkans, there was an Ottoman invasion & the invasion changed a lot.

Today, Albania consists of 35% Muslims, 34% Catholic & Orthodox, & the rest belongs Atheists, Agnostics & Protestants.

More and more Albanians though are going back to their Christian roots.