And as for the image twelve cubits high, we may express the same doubts. Ctesias seems to have received better information as to how these figures were made than Herodotus, and, through Diodorus, he tells us that they consisted of metal plates beaten into shape with the hammer.[232] Whether Ctesias or his informants did or did not exaggerate their true dimensions (Diodorus speaks of a Bel forty feet high), or whether these figures were of gold or gilded brass, is of comparatively slight importance; we are interested chiefly in the information he gives as to the method of fabrication. Ever since the discovery of the Balawat gates proved to what a height the student art of Assyria carried the manipulation of metal by the _repoussé_ process, we have had no difficulty in believing that the sculptors of Babylon in the time of Nebuchadnezzar could build up images of colossal size and fine decorative effect by means of plaques united with rivets. If we may believe the rest of Diodorus’s description, the Chaldæan artists combined the glory of gold and silver with the purity of ivory and the bright and varied colours of precious stones. And all this we see good reason to admit when we have examined at the British Museum those ivories in which lapis lazuli and other substances of the same kind even now fill up the hollows of the design, while the field still glitters here and there with some last fragments of the gold with which it was once incrusted. The skilful workmen who discovered the secret of this kind of mosaic, may very well have learnt to combine these beautiful materials so well that the statues upon which they were used would even have rivalled the chryselephantine masterpieces of Phidias; in richness and harmony of tones, at least, if not in nobility and purity of form. § 6. _Assyrian Sculpture._ Assyrian sculpture is far from leading us into the remote centuries from which some of the Chaldæan works must date. It had no period of infancy or childish effort. The Semites of the north were the pupils of their southern brothers, from whom they obtained an art already mature. The oldest known Assyrian monument dates from the reign of Tiglath-Pileser I., or about the end of the twelfth century B.C.; it is a bas-relief chiselled upon a rock near the sources of the Tigris, about fifty miles north of Diarbekir and near the village of Korkhar. It represents the king standing upright, his right hand extended and his left holding a sceptre; at present, however, we only know it by the very poor sketch given by Professor Rawlinson.[233] It is almost the only monument extant from the time when the capital of the monarchy was on the site now known as _Kaleh-Shergat_. One other may be named, the female torso in the British Museum, to which we have already referred;[234] on it the name of Assurbilkala, who succeeded Tiglath-Pileser I., may be read.