“The illusionism of the architectural framework in which it is set is characteristic of painting in Italy at [the Hellenistic and Roman] period. Ambitious—spatial and not flat—decorative schemes appeared early in the first century BC, visually enlarging the space of rooms with columns, entablatures and other architectural elements. . . . Later, a further step was taken by visually opening the wall, sometimes completely, sometimes with make-believe windows, to disclose vistas of colonnades stretching into the far distance. In the first century AD this imaginary architecture was treated with increasing fantasy to conjure up buildings of a more insubstantial elegance than any that could be erected on earth. . . .

These various types of painting are usually categorized as the Pompeiian Syles I, II, III and IV . . . [because] by far the largest number of examples have survived there. One room in the house of evidently prosperous merchants combines all four illusionistic systems or styles—a dado of simulated panels of rare marbles; pictures hung on or set in the wall and surrounded by frames which seem to project forwards; windows opening on to views of airy structures; and, above, statues placed on top of the wall, beyond which fanciful buildings may be glimpsed in space.”

—Hugh Honour & John Fleming, from The Visual Arts: A History, 1982.