The origin of the Trinity or the division of "God" into the Father, Son, and Holy Ghost was considered by some at various times to be a form of "polytheism," since it wasn't a part of the original doctrines of Jesus Christ.... again just a point that has been leveled by others not me.
Moreover this element found itself into even Protestantism as well, and a variety of other variations on Christianity. Of course, the controversy doctrine found it's way into other discussions and discussions on religion and Christianity generally. For instance, the Methodists were accepting of most of the central creeds however their leader John Wesley was later troubled by the elements specifically in the Athenasian Creed regarding condemnation for all those who were not aware of important elements and thus the only people would be saved were trained clergy and such members, so it would condemn everyone who was not a part of this kind of specialized class.
Others such as the Presybterians or Anglicans or various members of various churches were alternately more accepting or less accepting of the concept of the Trinity and elements of the Athenasian Creed.
Anyway, frustration with Trinitarian elements ultimately found it's most ardent expression in the form of the "Jehovah's Witnesses" who advocated by their own words a return to "1st Century" christianity, which meant denying pretty much most of the creeds and an acknowledgement of the central force behind Christianity "God" himself (or Jehovah).
Obviously, all these religions all have separate elements such as Jehovah's witnesses emphasis on Satan and Armageddon. But anyway, if we're just talking about run-of-the-mill "Catholicism" it seems to wise just what that means in specific different contexts because oftentimes it's hard to understand what that means with so many variations on "Christianity" that people as I say in the wikipedia will say accords with this or that.
Anyway, for my own part, it seemed to me that saying LOTR represents "Catholicism" or that "Catholicism" must automatically mean "Christianity" would be a bit of a stretch based on all the things I've read, some people seem to think the issue is more complicated than that. But as I say, that's not me that's the people who are telling me more or less through wikipedia and such...
Going off gut and instinct I don't think Tolkien was trying to make a "Catholic" work or a "Viking" work I think he was combing different elements, the end result is as I've stated apparently more Viking than Christian, but could hardly be easily summarized as belonging to both.