The history of ancient decorative wall-painting has yet to be written. The attention of the whole world was attracted by the wonderful discoveries made in Pompeii, and indeed for many years Pompeii stood for ancient decorative wall-painting in general.That Pompeii so completely overshadowed modern ideas on the evolution of this art is due in great measure to the fact that at Pompeii it had found a wonderful exponent and explorer in the late Professor August Mau. His book dealing with the Pompeian decorative mural painting at once became a classic and influenced profoundly text-books and popular works on the history of ancient art and customs.Two facts, however, should be borne in mind. First, that the decoration of Pompeian houses illustrates the art of one epoch. only—the Hellenistic and the earlier Roman Empire, except for a few examples from a still earlier age, and those not before the third century B.C. Also it should be remembered that this art at Pompeii can be taken as characteristic only of Italy and indeed only of Southern Italy; it does not follow that it developed on the same lines in other regions of the ancient world.