These fragments, taken altogether, show that a certain effort was made to produce decorated pottery towards the end of the Assyrian period. Why was the attempt not carried farther? Why were earthenware vases not covered with ornamental designs that might be compared for richness and variety with those chiselled in or beaten out of stone or wood, ivory or metal? The reason may, we think, be guessed. Clay appeared such a common material that they never thought of using it for objects of luxury, for anything that required great skill in the making, or in which its proprietor could take any pride. When they wanted fine vases they turned to bronze; bronze could be gilded, it could be damascened with gold and silver, and when so treated was more pleasing to the eye and more provocative of thought and ingenuity on the part of the artist than mere clay. It was reserved for Greece to erect the painted vase into a work of art. Her taste alone was able to make us forget the poverty of the material in the nobility of the form and the beauty of the decoration; we shall see that her artists were the first to give to an earthenware jar or cup a value greater, for the true connoisseur, than if they were of massive gold or silver. During the period on which we are now engaged, the Mesopotamians sometimes attempted to cover their vases with enamel. The British Museum has several specimens of a pottery covered with a blue glaze like that of the Egyptian faïence.[364] Here and there the blue has turned green under the action of time. One of the vases reproduced above (Fig. 180) belongs to this class. Vases of the same kind, covered with a rather thick layer of blue and yellow enamel, have been found among the rubbish in the Birs-Nimroud at Babylon,[365] but it is difficult to fix an exact date for them with any confidence. On the other hand, it is generally agreed that the large earthenware coffins brought from the funerary mounds of Lower Chaldæa are very much later. In style the small figures with which they are decorated resemble the medals and rock sculptures of the Parthians and Sassanids.[366]