In 1221 the young Dominican order took on a new member who would ultimately be known as Peter Martyr. Young Peter's parents had been members of the Cathari sect, but Peter was drawn to the Dominicans while a student at the University of Bologna.

A gifted and zealous speaker, Friar Peter became known for his preaching throughout Lombardy. But his notoriety begat jealousy and suspicion. He was accused of immorality (letting women into his monk's cell) and he argued with far too much success and conviction against his old alliance, the Cathari. He was so gifted at attacking this sect that they decided to send a "holy hit squad" to eliminate him.

Friar Peter and his companion Friar Dominic, were attacked and killed by two Cathari assassins in the wood while on their way from Como to Milan. T…