So far we have made no distinction between Chaldæan and Assyrian sculpture. They made, in fact, but one art. In both countries we find the same themes and the same treatment--the same way of looking at nature and the same conventional methods of interpreting it. The common characteristics are numerous enough to justify us in attributing to one and the same school the works produced both in the southern and northern provinces. If we take them _en bloc_, and put them side by side with the productions of any other great nation of antiquity, we shall be at once struck by the close resemblance between all the monuments from the valley of the Tigris and Euphrates, whether they come from Sirtella or Babylon, Calah or Nineveh. The connoisseur can point out a Mesopotamian creation at a glance, mingled with works from Egypt, Phœnicia, or Greece though it may be. In order to define the Chaldæo-Assyrian style, he may take the first object that comes to hand, without caring much whether it come from the upper country or the neighbourhood of the Persian Gulf. And yet between those cities of primitive Chaldæa that almost rivalled Memphis in age, and the towns of Assyria which only commenced to flourish in centuries that we may almost call modern, it is impossible that the spirit of the plastic arts and their executive processes can have remained without change. Between the earliest and the latest monuments, between the images of Gudea and those of Assurbanipal, there are, at least, shades of difference. It is certain that the old Chaldæan art and the art of Assyria were not two different arts, but they were two successive movements of the same art--two phases in its development. We have still to distinguish between these two phases by studying, one after the other, the history of Chaldæan and that of Assyrian sculpture. In the course of this study, and especially in the case of the older civilization, we shall encounter many gaps. The monuments are few, and, even of those that we have, many are not a little embarrassing. They are often uninscribed and we are then without even the help afforded by the language and the style of the character in fixing a date. Fortunately this is not always the case; there are often indications that enable us to form certain groups, and, if not to assign absolute dates, at least to determine their relative places in a chronological series.