Nevertheless, carvings in ivory of the Roman imperial times before Constantine are extremely scarce. In the superb collection in the South Kensington museum there are two only which can safely be so attributed. One is the fragment, no. 299; the other is the beautiful leaf, no. 212. The British museum (not to mention a large number of fragments chiefly of caskets or decorations of furniture, tesseræ and tickets of admission to theatres and shows, dice, and the like) possesses a few pieces, of which one is extremely fine in character and in good preservation. The subject is Bellerophon, who is represented on Pegasus, killing the Chimæra; and it is executed in open work. The age is somewhat doubtful. Professor Westwood places it as early as the third century, and his judgment must be treated with great deference. Others, of no slight authority, are indisposed to give it an earlier date than the fourth century. This admirable ivory has somewhat of the character of the book-cover in the Barberini collection, engraved by Gori, in the second volume of his great work on diptychs. That famous piece is not perfect, nor is there any name upon it. Gori fairly argues that it represents the emperor Constantius, about the year 357. The Bellerophon is of finer work. The gradual and uninterrupted decline of art from the days of Augustus is to be traced as distinctly in the ivories which have been preserved as in ancient buildings. But we can scarcely agree with D’Agincourt as regards its rapidity. Speaking of sculpture generally, he says: “On vit celle-ci successivement grande, noble, auguste sous le prince qui mérita ce nom; licencieuse et obscène sous Tibère; grossièrement adulatrice sous Caracalla; extravagante sous Néron, qui faisait dorer les chefs-d’œuvre de Lysippe.” D’Agincourt probably refers to the barbarism of Caligula, who proposed to put a head of himself upon the Olympic Zeus by Phidias; or to Claudius, who cut the head of Alexander out of a picture by Apelles, to replace it with his own. Suetonius has recorded the first of these atrocities (can we speak of them by a lighter name?) and Pliny the last. In the collection given to the town of Liverpool by Mr. Mayer there are two very celebrated pieces, possibly of the third century; they were originally the leaves of a diptych. On one is Æsculapius, on the other Hygieia. CHAPTER III.