This great work was found in the House of the Faun at Pompeii in the year 1830, and is immeasurably superior to anything of its kind hitherto found in that buried city. It has, no doubt, been a copy in mosaic of a picture or fresco painted by a Greek artist. Important portions of the work are missing, but enough remains to testify to the beauty and greatness of this monument of Grecian art. Fig. 289 represents the head of a Persian soldier in the mosaic. A border was found with this work which represents a river with alligators, hippopotami, aquatic birds, and river plants, all disposed in a careless manner; this border is evidently a later Roman addition to the work. Another antique mosaic picture in the Museum at Naples is the seated figure of the tragic poet found in a house at Pompeii. Fountains, columns, dados, wall panels, as well as floor decorations, were common objects of mosaic treatment with the Romans, and many houses of the better classes at Pompeii have been lavishly decorated with this imperishable material. A singular peculiarity was the almost exclusive representation of the human figure on floors, while the wall spaces only received ornamental compositions. [Illustration: Fig. 289.—Head in Mosaic, from the “Battle of Issus.”] It appears from this that the Romans never thoroughly understood the true value of mosaic as a means of architectural decoration, and it was not until about the fourth century of our era that the walls and vaults of churches at Rome were treated with pictorial mosaic. For a long time in Italy the character of the design was strongly influenced by the old classic traditions, which impregnated the germs of the early Christian art of the catacombs of S. Calixtus and S. Agnese (see Figs. 332, 333, former vol.). This influence hardly ever passed away from the works of Italian artists, for down to the sixteenth century there has been many examples of church decoration in which a mixture of Pagan and Christian elements are found. The remaining mosaics of the central cupola in the church of S. Constance at Rome consist of a Pagan composition—the “Triumph of Bacchus”—worked out in the Roman style, and another vaulted compartment in the same church has a mosaic decoration consisting of a vine spreading over the whole surface, amongst the branches and leaves of which are children gathering the grapes. At two of the sides are grape-laden waggons drawn by oxen, and figures pressing out the grape juice in the vats. From the subjects of the mosaics in this building it was formerly thought to be a temple of Bacchus; but as the vine is one of the commonest symbols of the Christian faith, and as a mixture of Christian and Pagan elements was a very common occurrence in the age of Constantine, there is no hesitation in describing these mosaics, and the church itself, as early Christian work.