God of truth, You bestowed on Blessed Innocent the gifts of knowledge and prudence and made him a promoter of peace and unity. By the help of his prayers may we cherish what is of heaven and in perfect unity follow what is right.
A 13th century Dominican friar known for his distinction in theology, Pierre of Trarantaise, was known as the most famous doctor. He served the Order of Friars Preachers as a prior provincial and the Church as the Archbishop of Lyons and later as the Cardinal-bishop of the ancient See of Ostia. At the Council of Lyons II and preached at the funeral of Saint Bonaventure.
In 1276 he was elected the Bishop of Rome --the Pope of the Roman Church-- the first of the Dominicans to serve in such manner, though only for six months. He's the very likely choice of popes who influenced the change of papal attire in that he likely continued to wear his Dominican habit after his election to the Chair of Peter. More on Pope Blessed Innocent V