Le Corbusier was visionary writer, theorist, and architect, and a lesser-known painter. Born Charles-Édouard Jeanneret, he adopted his moniker when he began to author architectural designs and paintings. He had a fascination with proportion, modularity, and geometry, often taking his cue from classical architecture theory. His designs, however, were modernist and industrial. He fondly called houses “machines for living in,” and said that the base principal for design is that “it must be beautiful.” Le Corbusier was interested in solving what he called the problem of urban co-habitation, and produced a great number of designs for houses and apartment buildings. Le Corbusier worked at the atelier of Peter Behrens, the training grounds of other architectural masters like Mies van der Rohe and Walter Gropius.