This Wikipedia article may be of some help: http://en.wikipedia.org/wiki/Catharism
The article offers an historical development summary: "The Cathars were largely a homegrown, Western European/Latin Christian phenomenon, springing up in the Rhineland cities (particularly Cologne) in the mid-12th century, northern France around the same time, and particularly southern France—the Languedoc—and the northern Italian cities in the mid-late 12th century."
Catharism is of course not Roman Catholic doctrine, but at least historically speaking it arose within the Roman Catholic Church. The article claims that the origins of Catharism were motiviated by "what they perceived to be the moral, spiritual and political corruption of the Church. They claimed an Apostolic succession from the founders of Christianity, and saw Rome as having betrayed and corrupted the original purity of the message, particularly since Pope Sylvester I accepted the Donation of Constantine (which at the time was believed to be genuine)."
Hope that helps.