1398-1444. Cardinal-bishop of Tusculum and papal legate. Born of a distinguished Roman family, he entered the service of the papal court and carried out several important missions. In 1419 he was in Bohemia on a mission against the Hussites; in 1425 he represented the pope in France and in 1426 in England. In that year also he was created cardinal. He was present, as papal legate, at Domazlice in 1431 when the Czechs defeated the German princes. He was appointed by Martin V to be president of the . The rout at Domazlice convinced him of the need for a general council to deal with Hussitism. He tried to persuade to cooperate with the council, but after the council divided and moved to Ferrara, he played a leading part in the negotiations for union between the Roman and Greek churches. Cesarini went to Hungary in 1442 to preach the crusade against the Turks. In 1444, due to his influence, the Peace of Szegedin was repudiated by King Ladislaus. In the renewed war, Cesarini, along with Vladyslav III, king of Poland and Hungary, was killed at the final, fatal battle of Varna in Bulgaria.