(1481-1536) Sienese High Renaissance architect. His most important buildings are found in Rome. His first significant work is the Villa Farnesina 1509–11, inspired by Raphael and yet more delicately decorative. He succeeded Raphael as architect to St Peter's 1520, but returned to Siena 1527, after the Sack of Rome, where he worked with Antonio da Sangallo the Younger on the Villa Caprarola 1530. His final work, the Palazzo Massimo alle Colonne, Rome, 1532–36, reflects in its unorthodoxy a move away from Renaissance Classicism toward Mannerism.