Cosmato's fourth son, Giovanni, first appears in an independent work in 1296, when, on the elegant sepulchre of Bishop Durante, he signs—"Jo͞hs filius Magri Cosmati fec̄ hoc op." Similar epigraphs are on the tomb of Cardinal Gonsalvo in S. Maria Maggiore, and a monument to Stefano de' Surdi in Santa Balbina.
In all these works of the Cosmati, Camille Boito finds signs of Lombard principles, and traces in the development of style from father to son the same gradual movement from older forms towards the Gothic, which we notice between Jacopo Tedesco and Arnolfo, and between Niccolò Pisano and his son Giovanni. Living in Rome, however, the Cosmati never really took up the Gothic style, as it developed further north; but always kept nearer to classical forms, and so prepared Rome for the Renaissance style, which arose from the humanist movement in the Cinque-cento epoch.
The next great patron of the Lombard Guild in Rome was Pope Nicholas V. (Thomas of Sarzana), of whom Gregorovius said—"This man had only two passions—collecting books and building." His dominating idea was the directing of a new Renaissance. According to him, "Rome ought to become the imperishable monument of the Church, or rather the Papacy, and re-arise in admirable magnificence before the eyes of all people."[298] Nicholas V. had the first idea of the rebuilding of St. Peter's, and the Vatican, but one man's life was not long enough for such great works. He, however, restored the Campidoglio, Castel S. Angelo, San Todaro, S. Stefano Rotondo, the palace of S. Maria Maggiore, the fountain of Trevi, the walls of Rome, and several of the State fortresses.
Candelabrum in S. Paolo at Rome, 12th century.
He got some of his architects, such as Leon Battista Alberti and Rossellino, from the Florentine Lodge, but by far the greater part of them were Lombards. The chief of these was Master Beltramo da Varese, of whom we have heard much in the Lombard Lodges. With him were his nephew Maestro Pietro di Giovanni, Maestro Paolo da Campagnano (a village near Varese), and Maestro Giacomo di Cristoforo. Rossellino had begun the works at St. Peter's in a kind of reverse fashion, starting with the apse. The continuation of this tribune was confided to Maestro Beltramo, who set to work in good earnest. He made vast lime and brick furnaces, filled the laborerium with wood, ropes, ladders, etc., engaged sub-architects and Magistri with bands of workmen under them, most of whom came down from the Como region. In fact, there was an army of Lombards.[299] The registers of the Opera, now in the Vatican, mark large payments to Magistro Beltramo and his nephew Pietro di Giovanni, who became chief architect after his uncle's death.
Besides the Tribune of St. Peter's, the two relatives were employed to rebuild the Campidoglio. Muntz publishes some notes taken from the registers of the Apostolic Camera, recording payments made between 1447 and 1448 to Maestro Beltramo, and some of his associates (socii), for the roof and marble windows of the Campidoglio and the palace of the Conservators. In 1452 Pietro da Varese is found continuing the work alone. The documents recently published from the registers of the Vatican have these entries—