Palladianism is a style based on the designs of the 16th-century Italian architect, Andrea Palladio (1508-1580). Palladio was inspired by the buildings of ancient Rome. In turn, British designers drew on Palladio's work to create a Classical British style. Palladian exteriors were plain and based on rules of proportion. By contrast, the interiors were richly decorated. Palladianism was fashionable from about 1715 to 1760.