Pope Nicholas V, born Tommaso Parentucelli, was head of the Catholic Church and ruler of the Papal States from 6 March 1447 until his death, in March 1455. Pope Eugene IV made him a cardinal in 1446 after successful trips to Italy and Germany, and when Eugene died the next year, Parentucelli was elected in his place. He took his name Nicholas in memory of his obligations to Niccolò Albergati.

Pope Eugene IV, born Gabriele Condulmer, was head of the Catholic Church and ruler of the Papal States from 11 March 1431 to his death, in February 1447. Condulmer was a Venetian, and a nephew of Pope Gregory XII. In 1431, he was elected pope.