Architect and engineer, born in the Ticino, Switzerland. He settled in Rome, where he worked for Cardinal Montalto, the future Pope Sixtus V (1585–90), for whom he designed the villa on the Quirinal (1576–88). In 1585–6 he made his name by re-erecting the huge Egyptian red-granite obelisk from the Circus Gai et Neronis (but originally in Alexandria), in the centre of the piazza in front of St Peter's basilica, and also re-erected the ancient obelisks at Santa Maria Maggiore (1587), San Giovanni in Laterano (1587–8), and Piazza del Pòpolo (1589). Thereafter he built the Lateran Palace (1585–9), the Vatican Library (1587–90), and supervised the erection of the dome of St Peter's under della Porta (1588–90). His other major contributions in Rome were the laying out of new streets, including the Via Felice (1585–9), and other town-planning improvements ordered by Sixtus V. In 1593 he moved to Naples, where he built the Palazzo Reale (1600–2).
Architectural Review, cxi/644 (April 1952), 217–26;D. Fontana (1604);Muñoz (1944);Roullet (1972);Wittkower (1982)