James of Viterbo

James of Viterbo, known in Latin as Jacobus de Viterbo and in Italian as Giacomo da Viterbo or Giacomo Capocci, was an Augustinian friar, scholastic theologian, and prelate of the late thirteenth and early fourteenth centuries. He was born in Viterbo, in the Papal States of central Italy, around the middle of the thirteenth century; an exact year of birth is not securely documented. As a young man he entered the Order of Hermits of Saint Augustine in his native city. The Augustinians sent him to the University of Paris, then the foremost center of theological study in Latin Christendom, where he studied under Giles of Rome, the order's leading master and a principal interpreter of Augustine in conversation with Aristotle.

At Paris, James proceeded through the theological curriculum and became a master of theology in the 1290s. He taught as a regent master in the Augustinian school there and took part in the quodlibetal and disputed questions that shaped late scholastic debate. His surviving academic work includes questions on the Sentences of Peter Lombard, quodlibetal questions, and treatises on the soul and on metaphysical themes. He is generally counted among the Augustinian school that sought to combine a strong Augustinian theological inheritance with the newly dominant Aristotelian philosophy, though his positions are not simply identical with those of Giles of Rome.

James's most widely discussed work is the treatise De regimine christiano (On Christian Government), composed about 1301–1302 and dedicated to Pope Boniface VIII. Written in the climate of the conflict between the papacy and King Philip IV of France, and close in time to the bull Unam Sanctam, the work presents the Church as a kingdom and develops a theory of papal plenitude of power in temporal as well as spiritual affairs. Historians of political thought often treat it, together with Giles of Rome's De ecclesiastica potestate, as a major statement of hierocratic papalism at the turn of the fourteenth century. James argues that royal power is in some sense ordered to and perfected by papal authority, while still allowing a distinction of functions between the two powers.

In 1302 Boniface VIII named him Archbishop of Benevento and, later the same year, transferred him to the metropolitan see of Naples, in the Angevin kingdom of southern Italy. As archbishop of Naples he served during the reign of Charles II of Anjou. He died in Naples in 1308. His cult as a blessed was later recognized by the Catholic Church; Pope Pius X confirmed his beatification in the early twentieth century. He is remembered chiefly as a theologian of the Augustinian order and as an early systematic writer on the Church as a political community, rather than as a figure of popular devotion with extensive recorded patronages.