Pope (1277-1280), original name Giangaetano Orsini.
A son of the powerful Matteo Rosso Orsini, a senator of Rome, Giangaetano became a cardinal in 1244 while still in his twenties. He joined Pope Innocent IV in his flight from Rome in 1246 and served papal interests in France, England, and Italy. In 1261 Urban IV named him cardinal-protector of the Franciscan Order, and he was one of four cardinals who crowned Charles I of Anjou as king of Sicily in 1265. Giangaetano was elected pope on 22 August 1277 at Viterbo, succeeding John XXI.
Nicholas opposed the political ambitions of Charles of Anjou and encouraged a stricter definition of poverty for the Franciscans in the constitution Exiit qui seminat, issued in 1279. Nicholas demanded that the Byzantine clergy renew the oath of union sworn at the Second Council at Lyons. He further insisted that those members of the Greek Orthodox clergy who had opposed the union receive absolution from papal envoys, a move that stiffened Byzantine resistance to the union with the Latins. Nicholas died on 22 August 1280 at Soriano near Viterbo. In Dante’s Inferno Nicholas appears in the eighth level of hell, tormented for simony.