Papal States and the Holy Roman Empire, regarding undercutting or at least containing the reforming decrees of the Council of Basel (1431–1439). Papacy Parentucelli's successful diplomacy gained him the reward, on his return to Rome, of the title Cardinal-Priest of Santa Susanna in December 1446. At the papal conclave of 1447 he was elected pope in succession to Eugene IV on 6 March. He took the name Nicholas in honour of his early benefactor, Niccolò Albergati. In only eight years, his pontificate delivered important achievements in the political, scientific, and literary history of the world. Politically, he needed to repair relationships which had broken down in the pontificate of Eugene IV. He called the congress which produced the Treaty of Lodi, secured peace with Charles VII of France, and concluded the Concordat of Vienna or Aschaffenburg (17 February 1448) with the German King, Frederick III, by which the decrees of the Council of Basel against papal annates and reservations were abrogated so far as Germany was concerned. In the following year he secured a still greater tactical triumph with the resignation of the Antipope Felix V on 7 April and his own recognition by the rump of the Council of Basel that assembled at Lausanne. In 1450, Nicholas held a Jubilee at Rome, and the offerings of the numerous pilgrims who thronged to Rome gave him the means of furthering the cause of culture in Italy, which he had so much at heart. In March 1452 he crowned Frederick III as Holy Roman Emperor in St. Peter's, in what was the last imperial coronation held in Rome. Within the city of Rome, Nicholas introduced the fresh spirit of the Renaissance both intellectually and architecturally. His plans were of embellishing the city with new monuments worthy of the capital of the Christian world. It was in recognition of this commitment to building that Leon Battista Alberti dedicated to Nicholas V his treatise De re aedificatoria. Rebuilding Rome His first care was practical, to reinforce the city's fortifications, cleaning and even paving some main streets and restoring the water supply. The end of ancient Rome is sometimes dated from the destruction of its magnificent array of aqueducts by 6th-century invaders. In the Middle Ages Romans depended for water on wells and cisterns, and the poor dipped their water from the yellow Tiber. The Aqua Virgo aqueduct, originally constructed by Agrippa, was restored