Similar to the early Christian Gnostics, there existed a sect in Southern France known as the Cathars, who considered themselves the only true Christians of their era. The Roman Orthodox church vehemently disagreed with this, of course, so just like Gnosticism, Catharism was outlawed and they too were hunted down as heretics. In fact, the Cathars were the first Christian group targeted by the Catholic Crusades, and the very first Inquisition was specifically created to torture Cathars...
