Roger entered the Benedictine order as a boy in 1301, at the Abbey of La Chaise-Dieu in the diocese of Clermont in the Auvergne. After six years there, he was directed to higher studies by the Bishop of Le Puy, Jean de Cumenis, and his own abbot, Hugues d'Arc. In 1307 he took up studies in Paris at the College de Sorbonne, where he entered the Collège de Narbonne. To support him, beyond what was supplied by his bishop and his abbot, he was granted the post of Prior of St. Pantaléon in the diocese of Limoges. In the summer of 1323, after Pierre had been studying both theology and canon law in Paris for sixteen years, the Chancellor of Paris was ordered by Pope John XXII, on the recommendation of King Charles IV, to confer on him the doctorate in Theology, a chair, and a license to teach. Pierre was in his thirty-first year. He lectured publicly on the "Sententiae" of Peter Lombard, and defended and promoted the works of Thomas Aquinas. He was appalled by the "Defensor Pacis" of Marsilius of Padua, and wrote a treatise in 1325 condemning its principles and defending Pope John XXII.