born April 12, 1484, Florence
died Aug. 3, 1546, Terni
Italian architect.
He was the nephew of the architects Giuliano da Sangallo (1445–1516) and Antonio da Sangallo the Elder (1460–1534). Throughout his career, Antonio worked on St. Peter's Basilica , first as Donato Bramante 's assistant and after 1520 as chief architect. His imposing Palazzo Farnese in Rome (1534–46), a fortresslike Florentine-style palace, exercised immense influence well into the 19th century. His wooden model of St. Peter's (1539–46) still stands in the Vatican Museum.