Blessed James of Viterbo (c. 1255 – 1308), known as Giacomo da Viterbo, Jacobus de Viterb(i)o, surname Capocci, and nicknamed Doctor speculativus, was an Augustinian friar and student of Giles of Rome.[1]
He was born in Viterbo, Italy. He was professor of theology at the University of Paris from 1293 to 1300.
He wrote on the relationship between ecclesiastical and temporal power in his book De Regimine Christiano. It argued that although human power alone is lawful, it could only be perfected through the influence of a spiritual power. Walter Ullmann[2] says that it was 'the first systematic exposition of the concept of the Church'.
He became Archbishop of Benevento in 1302, and Archbishop of Naples in 1303.
He died in Naples.