Christianity, specifically Roman Catholicism, is the most common religion in southern Europe. Countries like Italy, Spain, Portugal, and Greece have a majority of their population identifying as Catholic.
It's just Catholic, not Roman Catholic. Roman is an epithet first commonly used in England after the protestant revolt to describe the Catholic Church. It is never used by the official Catholic Church. That being said, historically, France, Spain, Portugal, and southern Europe, including Austria, southern Germany, Italy, along with Poland, Ireland, Malta, etc. were mostly Catholic. Before the protestant revolt, they were all Catholic.
Northern Europe had more protestants than Southern Europe, as Southern Europe remained Catholic/Orthodox. Scandinavia, Prussia, and Britain is mostly protestant while Germany, Italy, and Spain are mostly Catholic and Greece is mostly Orthodox
Old Roman Catholic Church in Europe was created in 2000.
Roman Catholic Vicariate Apostolic of Southern Arabia was created in 1888.
Explorer Jacques Cartier came from France. As is the case now, France at that time was a largely Roman Catholic country.
One religion of Austria is largely Roman Catholic.
roman Catholicism
italian
The largest religious denomination in Europe is Roman Catholic.
I assume you mean Roman Catholic. If so, then: No, Greece is largely Greek Orthodox. As an anglo-catholic I believe that Orthodox Christians are members of a valid branch of the one, holy catholic and apostolic church. But they are not roman catholic.
Roman Catholicism has dominated Southern Europe since the Roman Empire adopted the religion of Christianity.