I used to believe that the Catholic Church was an invention of the Roman Emperor Constantine in the mid-fourth century. I was told at 14 years of age by my 17 year old bible scholar friend that Constantine had made a deal with the devil to legalize Christianity and incorporate paganism into it and that was the start of the Catholic Church. The "real Christians" had to "go underground" to avoid persecution by this pagan Catholic church. Made sense to me and not having had a single lesson in the history of western civilization, I accepted what I was told as true. My anti-Catholic bias made it easy for me to accept "hook, line and sinker" anything that was against this church.
Funny thing though, there is no history of any church ever existing back then but the Catholic Church. However, in a recent on-line debate with a non-catholic, I was told that "the victors always get to write the history books." This actually was also quoted from a popular movie that opened this weekend that seeks to blaspheme and undermine our faith, but it was being used to convince me I was wrong because the Catholic church "has always suppressed the truth."
I later learned the term "Catholic" (universal) was applied and used by the church in 107 AD and probably earlier. A more cogent discussion can be found at : http://www.ewtn.com/faith/teachings/churb3.htm