Dominican. Friend of Saint Dominic de Guzman. Chief assistant to the inquisitor Peter Seila when he was investigation the Albigensians. Basing their operations in a farmhouse outside Avignonet, France, he and his brother missioners worked against heresy. Murdered by Albigensian heretics while singing the Te Deum on the eve of Ascension. One of the Martyrs of Toulouse.
- against neuralgia (due to miracle healing of one of the Dominican sisters of the monastery of Prouille, France)
- “Blessed William Arnaud“. CatholicSaints.Info. 12 August 2015. Web. 23 January 2017. <>