Fresco, or water-color, on fresh plaster, was used for coloring walls, which were divided into compartments or panels.  The composition of the stucco, and the method of preparing the walls for painting, is described by the ancient writers:  “They first covered the walls with a layer of ordinary plaster, over which, when dry, were successively added three other layers of a finer quality, mixed with sand.  Above these were placed three layers of a composition of chalk and marble-dust, the upper one being laid on before the under one was dry; by which process the different layers were so bound together that the whole mass formed one beautiful and solid slab, resembling marble, and was capable of being detached from the wall and transported in a wooden frame to any distance.  The colors were applied when the composition was still wet.  The fresco wall, when painted, was covered with an encaustic varnish, both to heighten the color and to preserve it from the effects of the sun or the weather; but this process required so much care, and was attended with so much expense, that it was used only in the better houses and palaces.”  The later discoveries at Pompeii show the same correctness of design in painting as in sculpture, and also considerable perfection in coloring.  The great artists of Greece—­Phidias and Euphranor, Zeuxis and Protogenes, Polygnotus and Lysippus—­were both sculptors and painters, like Michael Angelo; and the ancient writers praise the paintings of these great artists as much as their sculpture.  The Aldobrandini Marriage, found on the Esquiline Mount during the pontificate of Clement VIII., and placed in the Vatican by Pius VII., is admired both for drawing and color.  Polygnotus was praised by Aristotle for his designs, and by Lucian for his color.

Dionysius and Mikon were the great contemporaries of Polygnotus, the former being celebrated for his portraits.  His pictures were deficient in the ideal, but were remarkable for expression and elegant drawing.  Mikon was particularly skilled in painting horses, and was the first who used for a color the light Attic ochre, and the black made from burnt vine-twigs.  He painted three of the walls of the Temple of Theseus, and also the walls of the Temple of the Dioscuri.

A greater painter still was Apollodorus of Athens.  Through his labors, about 408 B.C., dramatic effect was added to the style of Polygnotus, without departing from his pictures as models.  “The acuteness of his taste,” says Fuseli, “led him to discover that as all men were connected by one general form, so they were separated each by some predominant power, which fixed character and bound them to a class.  Thence he drew his line of imitation, and personified the central form of the class to which his object belonged, and to which the rest of its qualities administered without being absorbed.  Agility was not suffered to destroy firmness, solidity, or weight; nor strength and weight, agility.  Elegance did not degenerate