After his return to Rome, he was nominated as the architect of the pontifical palaces by his Florentine countryman Pope Clement XII Corsini, a position later confirmed by Benedict XIV. Fuga's masterwork is the "palazzo"-like screening façade he erected in front of the basilica of Santa Maria Maggiore (1741–1743). A similar project, considered to be a dry run for the greater project, is the façade he provided for Santa Cecilia in Trastevere. In both cases, care was taken not to mar the mosaics of the medieval fronts that still lie behind Fuga's screens, which provided a narthex for each ancient basilica.