GUILLAUME PEYRAUT (also known as Peraldus or Péraud, erroneously called “archiepiscopus Lugdunensis”) was a Dominican moralist. He was born around the year 1200 at Peyraud in the Ardèche department and died after 3 February 1261 at Lyon. He was one of the greatest preachers and moralists of his century. He probably entered the Dominican convent at Lyon between 1236 and 1240. In 1249 the Franciscan Salimbene attests to his activity as a preacher and confessor at Vienne. He served several times as prior of the Lyon convent, notably in 1261. His *Summa* exerted a great spiritual influence.
Among his writings are:
*Summa de vitiis et virtutibus* (Basel 1469; 14 other editions before 1500 and 23 thereafter);
*Sermones de dominiciis et festis* (Ulm 1486, etc.);
*Expositio professionis monachorum* (Paris 1500, etc.);
and probably *De eruditione principum* (Rome 1570), which has been attributed to St Thomas Aquinas.