James of Viterbo

Giacomo da Viterbo OSA (c. 1255 – c. 1307), born Giacomo Capocci (nicknamed Doctor speculativus), was an Italian Roman Catholic Augustinian friar and Scholastic theologian, who later went to hold a number of ecclesiastical posts.

Giacomo was born in Viterbo in the Papal States around the year 1255. Little information is available regarding his early years. It is presumed that he joined the Order of St. Augustine around the year 1272, and he is first mentioned in the surviving historical records in the year 1283 in the capitular acts of the Augustinians’ Roman province as a recently appointed lecturer in the Convent of Viterbo, meaning that he must have spent the previous five years from 1278 to 83 in the University of Paris, because the Augustinian Order required its lecturers to be trained in Theology in that city for a duration of five years. Giacomo returned to Paris soon after his appointment in Viterbo because his name is again mentioned in the capitular acts in 1288, where he is mentioned as holding a Bachelor of Theology degree from the University of Paris. After the completion of his studies, Giacomo was appointed Master of Theology in either 1292 or 1293, and taught in Paris for the next seven years, during which time his output was extensive as all of his works in the fields of speculative theology and metaphysics date from this time. Around the year 1300, he was named as a member of the governing council of the Augustinian Roman Province by the Augustinians’ General Chapter, and in May 1300, he became regent master of the order's studium generale in Naples. These two years proved to be the last of his academic career, because Pope Boniface VIII appointed him as Archbishop of Benevento in September 1302, possibly as a sign of gratitude for Giacomo's support for the Pope against the King Philip IV in his treatise, De regimine christiano (On Christian Rulership). In December 1302, at the request of King Charles II of Naples, Giacomo was transferred to the Archbishopric of Naples, and remained there until his death in 1307.

He was beatified by Pope Pius X on 14 June 1914.

The works authentically attributed to him are listed as follows:

• Lectura super IV libros Sententiarum
• Quaestiones Parisius disputatae De praedicamentis in divinis
• Quaestione de animatione caeli
• Quaestiones disputatae de Verbo
• Quodlibeta quattuor
• Abbreviatio In Sententiarum Aegidii Romani
• De perfectione specierum
• De regimine christiano
• Summa de peccatorum distinctione
• Sermones diversarum rerum
• Concordantia psalmorum David
• De confessione
• De episcopali officio

• H. X. Arquillière (1926), Les plus ancien traité de l'Eglise: J., De regimine Christiano
• R. W. Dyson (1995), James of Viterbo: On Christian Government (De regimine Christiano)