The ancient visitor would have found painting even more popular than sculpture in Rome’s temples and dwellings, porticoes and squares. He would have come upon many works of old masters there- Polygnotus, Zeuxis, Apelles Protogenes, and others- as dear to the opulent Empire as the paintings of the Renaissance are to rich America; and he would have seen in greater abundance, through their better preservation, the products of Alexandrian and Roman schools. The art was old in Italy, where every wall craved ornament. Once even Roman nobles had practiced it; but the Hellenistic invasion had made painting Greek and servile, and at last Valerius Maximus marveled that Fabius Pictor should have stooped to paint murals in the Temple of Health. There were exceptions: toward the end of the Republic Arellius made a name for himself by hiring prostitutes to pose for his goddesses; in the time of Augustus a dumb aristocrat, Quintus Pedius, took up painting because his defect closed most professions to him; and Nero employed for the interior of his Golden House one Amulius, who painted with the greatest gravity, always in his toga.” But such men were rari nantes in the crowd of Greeks who, at Rome and Pompeii and throughout the peninsula, made copies or variations of Greek paintings on Greek or Egyptian themes. The art was practically limited to fresco and tempera. In fresco a freshly plastered wall was painted with water-moistened colors; in tempera the pigments were mixed with an adhesive sizing and laid upon a dry surface. Portrait painters sometimes employed an encaustic process in which the tints were fused in hot wax. Nero had his picture painted on a canvas 120 feet high- the first known use of this material. Painting, as we have seen, was applied to statues, temples, stage scenery, and great linen pictures intended for exhibition in triumphs or in the Forum; but its favored receptacle was the external or internal wall. The Romans seldom placed furniture against a wall or hung pictures there; they preferred to use the entire space for one painting, or for a group of related designs. In this way the mural became a part of the house, an integral item in the architectural design.