The Villa La Rotonda, which Andrea Palladio worked on from 1565, is located near Vicenza, in Northern Italy. Palladio's sketch very clearly reveals the references to ancient architecture.
Andrea Palladio (1508–1580), Villa La Rotonda, sketch, 1570, in: Palladio, Andrea: I quattro libri dell' architettura, Venice 1570, vol. 2, p. 17; source: Niedersächsische Staats- und Universitätsbibliothek Göttingen, shelf number 4 M ARCH I, 1293 RARA.