Neoclassical architecture is an architectural style produced by the neoclassical movement that began in the mid-18th century, manifested both in its details as a reaction against the Rococo style of naturalistic ornament, and in its architectural formulas as an outgrowth of some classicizing features of Late Baroque. In its purest form it is a style principally derived from the architecture of Classical Greece and Rome and the architecture of the Italian architect Andrea Palladio. In form, Neoclassical architecture emphasizes the wall rather than chiaroscuro and maintains separate identities to each of its parts.