mere wall-decoration for elaborate easel-paintings; but this was no new invention. It has been pointed out by Mrs Strong[1] that amongst the wall-paintings of Pompeii we can distinguish a group executed in bold dashes of colour—especially white—according to the principles of modern impressionism. The most striking example of this betrays its source of inspiration by its subject—the ceremony of the evening benediction in front of the temple of Isis (Plate V. fig. 27).
So far the paintings which we have considered can only be regarded as an extremely ingenious and, in the main, tasteful form of wall-decoration; they tell us little of that which we most wish to know—the style and treatment of substantive works of painting. The gap is in some measure filled by the central panels of Pompeian walls, which are usually adorned with subject-paintings, often mythological in subject, clearly marked off from the rest of the wall and intended to take the place of pictures. In the Architectural style these are usually framed in a species of pavilion or aedicula, painted in perspective;[2] but this motive gradually loses its importance. In the Third style (“ornate”) distinguished by Mau the architectural design ceases to be intelligible as the counterfeit of real construction, and becomes a purely conventional scheme of decoration; and in the Fourth or Intricate style, which again reverts to true architectural forms, however fantastic and bewildering in their complexity, the figure-subjects are plainly conceived as pictures and framed with a simple band of colour. The subjects of these frescoes are for the most part taken from Greek mythology, and it has been argued that in the main we have to deal with reproductions of Hellenistic paintings rather than of contemporary works of art. It is not to be denied that the motives of famous compositions of earlier date may have found their way into the repertory of the Pompeian artists; it is not unnatural, for example, to conjecture that the figure of Medea here reproduced (Plate VI. fig. 30) may have been inspired by the celebrated painting of Timomachus above-mentioned. But there are reasons for thinking that the debt owed by the Pompeian artists to the Greek schools of the Hellenistic age is not so direct as was believed by Helbig, whose Untersuchungen über die kampanische Wandmalerei won a general acceptance for the theory. It seems clear that in the central subjects of walls decorated in the Architectural style we are intended to see, not a picture in the strict sense, but a view of the outside landscape, generally with a small shrine or cult-statue as the centre of the piece; and the importance of the figure-subject was therefore at first subordinate. These subjects are, it is true, taken from Greek mythology, but this only proves that that source of inspiration was as freely drawn upon in the art as in the literature of imperial Rome. In the later styles figure-subjects Without landscape are extremely common, but it has been shown that, e.g. in the triclinium of the Casa dei Vettii, which is decorated with a cycle of mythological paintings, the lighting is carefully calculated with a view to illusionistic effect under the local conditions, so that the conception of an outlook into external space is not given up. We sometimes, as in one of the rooms in the “Farnesina” house, find framed pictures directly imitated, and here the models were clearly of a relatively early period; but this is exceptional. The Pompeian paintings, therefore, may fairly be used as evidence for the methods and aims of art in imperial Rome; and when allowance is made for their decorative character and hasty execution, we must admit that they give token of considerable technical skill—the modelling of figures is often excellent, the colour-scale rich, the “values” nicely calculated. The composition of subject-pictures is somewhat theatrical. Amongst the wall-paintings which have been preserved are some which from their classicistic style have been thought to represent Greek originals; the most famous is the “Aldobrandini Marriage” (Plate V. fig. 28), now in the Vatican library.. As a matter of fact, the composition is formed by the juxtaposition of sculpturesque types, after a fashion familiar to Roman wall-painters. Mention may here be made of the combination of ornamental work in plaster with painting which is found at Pompeii, in the work of the Flavian period at Rome, and in tombs of the 2nd century A.D. In the Augustan period we find exquisitely modelled relief-work in plaster, used to ornament vaulted surfaces in the “Farnesina” house; it might seem natural to treat of these under the heading of Sculpture, but in point of fact they are translations from painting into stucco. At a later time both painter and modeller worked in conjunction, with admirable effect; the results are best seen in the tombs on the Latin Way.
Little can be said as to Roman portrait-painting. We know that in this branch of art the technique generally used was that called “encaustic.” The colours were mixed with liquefied wax and fixed by heat; whether they were applied in a molten state or not has been disputed, but it seems more likely that the pigments were laid on cold, and a hot instrument used afterwards. Several examples of such wax-paintings have been found in Egypt, where it was the custom during the 2nd and 3rd centuries A.D. to substitute panel portraits for the plastic masks with which mummy-cases were adorned; but these cannot be described as works of high art, though they sometimes have realistic merit. A good example in the Berlin Museum (Antike Denkmäler, ii. pl. 13) is executed in tempera on primed canvas. The medium used in ancient as in medieval tempera painting appears from the statements of ancient writers to have been yolk of egg mixed with fig-sap or natural gums.
To the little we know of purely Roman painting something is added by that which we learn from the remains of the sister art of mosaic, which, being less easily destroyed, have survived in large numbers to the present day. It has been estimated by Gauckler that considerably more than 2000 mosaics with figure-subjects have been discovered; and the number is steadily increasing. For the origin of the art reference may be made to the article Mosaic, where the reader will also find an explanation of the essential differences of principle between the arts of painting and mosaic. It is to the credit of the Roman artists that they were, generally speaking, alive to this distinction of method, and did not seek to produce the impression of painting executed with a liquid medium by the use of solid materials. Indeed, it seems not improbable that in this respect they had a truer conception of the function of mosaic decoration than their Greek forerunners. Amongst the mosaics of Roman date which employ a large number of exceedingly minute cubes in order to produce an illusion akin to that of painting, the most conspicuous examples are the pavement in the Lateran Museum signed by the Greek Heraclitus, which appears to reproduce the “unswept hall” of Sosos of Pergamum (see Mosaic), and the Mosaic of the Doves from Hadrian's Villa, preserved in the Capitoline Museum, which may be supposed to have been inspired by the “drinking dove” of the same artist. The former of these contains about 120, the latter as many as 160 cubes to the square inch.
As shown in the article Mosaic, a distinction must be drawn between opus tessellatum, consisting of cubes regularly disposed in geometrical patterns, and opus vermiculatum, in which a picture is produced by means of cubes irregularly placed. The two methods were commonly used in conjunction by the Romans, who recognized that a pavement should emphasize the form of the room to which it belonged by means of a geometrical border, while figure-subjects should be reserved for the central space. A good example is furnished by a mosaic pavement discovered on the Aventine in 1858, and preserved in the Museo delle Terme (Plate VI. fig. 29). Enclosed within a geometrical framework of guilloches and scroll-work, diversified with still-life subjects and scenic masks which break its monotony, we find a landscape evidently taken from the banks of the Nile, as the hippopotamus and crocodile, as well as the papyrus and lotus, clearly show. These Egyptian scenes are likewise found
