Domenico Fontana (1543 – 28 June 1607) was an Italian architect of the late Renaissance, born in today's Ticino. He worked primarily in Italy, at Rome and Naples.
He was born at Melide, a village on the Lake Lugano, at that time joint possession of Swiss cantons of the old Swiss Confederacy, and presently part of Ticino, Switzerland, and died at Naples. He went to Rome in 1563, before the death of Michelangelo, to join his elder brother. He won the confidence of Cardinal Montalto, later Pope Sixtus V, who entrusted him in 1584 with the erection of the Cappella del Presepio (Chapel of the Manger) in Basilica di Santa Maria Maggiore, a powerful domical building over a Greek cross. It is a marvellously well-balanced structure, notwithstanding the profusion of detail and overloading of rich ornamentation, which in no way interferes with the main architectural scheme. It is crowned by a dome in the early style of S. Mario at Montepulciano. For the same patron, he constructed the Palazzo Montalto near Santa Maria Maggiore, with its skilful distribution of masses and tied decorative scheme of reliefs and festoons, impressive because of the dexterity with which the artist adapted the plan to the site at his disposal.
After the cardinal's accession as Sixtus V, he appointed Fontana Architect Of St. Peter's, bestowing upon him, among other distinctions, the title of Knight of the Golden Spur. He added the lantern to the dome of St. Peter's and proposed the prolongation of the interior in a well-defined nave.