What is a brief history on the idea that the Pope is the Antichrist?

I am quite familiar with the Reformers' opposition to the Papacy, and [many said the Pope is the Antichrist](http://en.wikipedia.org/wiki/Antichrist#Protestant_reformers) . What confuses me is this quote from that same page: >In calling the pope the "antichrist," the early Lutherans stood in a tradition that reached back into the eleventh century. Not only dissidents and heretics but even saints had called the bishop of Rome the "antichrist" when they wished to castigate his abuse of power. I was under the impression that the idea originated with the Reformers; however, it clearly did not. I would like a brief history of this idea up until the Reformers.