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. Pope Eugene 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.
The pontificate of Nicholas saw the fall of Constantinople to the Ottoman Turks and the end of the Hundred Years War. He responded by calling a crusade against the Ottomans, which never materialized. By the Concordat of Vienna he secured the recognition of papal rights over bishoprics and benefices. He also brought about the submission of the last of the antipopes, Felix V, and the dissolution of the Synod of Basel. A key figure in the Roman Renaissance, Nicholas sought to make Rome the home of literature and art. He strengthened fortifications, restored aqueducts, and rebuilt many churches. He ordered design plans for what would eventually be the Basilica of St. Peter.