Clement IV, d. 1268, pope (1265–68), a Frenchman named Guy le gros Foulques; successor of Urban IV. He was a lay adviser of King Louis IX of France, but after his wife's death he entered the church. As pope he continued the struggle against the Hohenstaufen by confirming the agreement with Charles I (Charles of Anjou) that gave Charles the crown of Naples, by raising an army for him, and by investing him with the kingdom. When Conradin attacked Charles, Clement had a crusade preached against him. He was a strong opponent of nepotism, and he was the patron of Roger Bacon. He was succeeded by Gregory X.