Pope from December 12, 1254 to March 25, 1261. Born in Anagni, France as Rinaldo Conti; died on March 25, 1261 in Viterbo, Italy. Of the house of Segni, he became cardinal-bishop of Ostia and was well advanced in years when elected pope. Although a man of great virtue, he was unable to cope with the difficult political conditions of his time. His crusade against the tyrant Ezzelino was successful, but the spirit of the Crusades was dying out and his expedition against the Tatars was unsuccessful. Rome and a large portion of Italy were lost to papal control during his reign.