Edsel Ford commissioned murals by Diego Rivera for DIA in 1932. Composed in fresco style, the five sets of massive murals are known collectively as "Detroit Industry, or Man and Machine". The murals were added to a large central courtyard; it was roofed over when the work was executed. The Diego Rivera murals are widely regarded as great works of art and a unique feature of the museum. Architect Henry Sheply, a close friend of Cret's would write: "These are harsh in color, scale and composition. They were designed without the slightest thought given to the delicate architecture and ornament. They are quite simply a travesty in the name of art." Their politically charged themes of proletariat struggle caused lasting friction between admirers and detractors.