Gundolfo
Gundolfo or Gundulf is purported to be a teacher of Proto-Protestant Christian doctrines in the early 11th century. Of Italian origin, he was said to be active in the bishopric of Cambrai-Arras in northern France (south of Lille) around 1025 during the episcopate of Bishop Gerard of Florennes.
Gundulfo rejected the sacraments and authority of the Catholic Church and claimed salvation by a righteousness based on his reading of the Gospels rather than on Catholic Church dogma. His teachings emphasized that salvation was achieved through a virtuous life of abandoning the world, restraining the appetites of the flesh, earning food by the labor of hands, doing no injury to anyone, and extending charity to everyone of their own faith.
Following a lengthy sermon by Gerard, followers of Gundulfo recanted their radical beliefs and were received back into the Church. The source of Gundolfo's teachings is unknown but may be compared to Catharism and to the Waldensians.
Details surrounding the remainder of Gundolfo's life are scarce, including when and where he died.