Pope (1265-1268). Clement IV was born at the end of the twelfth century in Saint-Gilles-du-Gard (Languedoc) as Guy Foucois (Gui Foulques).
After the study of law in Paris, he became a legal counselor to Count Alphonse of Poitiers and King Louis IX of France. He was repeatedly entrusted with enquêtes (judicial inquiries) and thus came into contact with the Inquisition in the Languedoc. As a result he wrote (around 1260) a manual for inquisitors, the Questiones quindecim ad Inquistores. After the death of his wife, he began an ecclesiastical career, becoming bishop of Le Puy (1257), archbishop of Narbonne (1259), and cardinal bishop of Sabina (1261). Although a legation to England failed in 1264, he was elected pope on 5 February 1265 and crowned ten days later.
Clement’s pontificate stood under the shadow of having to resolve the question of the succession to the kingdom of Sicily, left open after the death of his predecessor Urban IV. Clement succeeded in imposing stricter feudal obligations on Charles I of Anjou, and, although his policies were crowned with success by the investment of Charles with the kingdom of Sicily on 28 June 1265, he was faced with several setbacks because the king often failed to meet his obligations. Different projects for a crusade were never realized during his pontificate, but Clement succeeded in strengthening papal control of the church by reserving all vacant prebends to the pope (in the constitution Licet ecclesiarum of 1265). He died on 29 November 1268 in Viterbo, where he had continued building the famous papal palace.