 James was born in Viterbo around 1255. Nothing is known about the early years of his life. It is presumed that he joined the order of the Hermits of St. Augustine somewhere around 1272. He is first mentioned in 1283 in the capitular acts of the Roman province of his order as a recently appointed lecturer (lector) in the Augustinian Convent of Viterbo. This means that he must have spent the previous five years (i.e., 1278–83) in Paris, as the Augustinian order required its lecturers to be trained in theology in that city for a period not exceeding five years. James returned to Paris not long after his appointment in Viterbo, for he is mentioned again in the capitular acts in 1288, this time as baccalaureus parisiensis, i.e., as holding a bachelor of theology degree from the University of Paris. After completing his course of studies, James was appointed Master of Theology in 1292 (Wippel 1974) or 1293 (Ypma 1974), teaching in Paris for the next seven years. His output during that time was considerable. All of his works in speculative theology and metaphysics date from the Parisian period. In 1299–1300, he was named definitor (i.e., member of the governing council) of the Roman province by the general chapter of his order, and in May of 1300 he became regent master of the order’s studium generale in Naples.  These would be the last two years of his academic career, however, for in September 1302 he was named Archbishop of Benevento by Pope Boniface VIII, possibly in gratitude for the support James had shown for the papal cause in his great treatise, De regimine christiano (On Christian Rulership). In December of the same year, at the request of the Angevin King, Charles II, he was transferred to the Archbishopric of Naples. He remained in Naples until his death, in 1307 or 1308.