It is unnecessary, however, to pursue this subject any further.

But a few words must be added on the chief cities of the Empire, before this chapter is brought to a conclusion.
The cities of the Empire may be divided into those of the dominant country and those of the provinces.

Those of the dominant country were, for the most part, identical with the towns already described as belonging to the ancient Chaldaea, Besides Babylon itself, there flourished in the Babylonian period the cities of Borsippa, Duraba, Sippara or Sepharvaim, Opis, Psittace, Cutha, Orchoe or Erech, and Diridotis or Teredon.

The sites of most of those have been described in the first volume; but it remains to state briefly the positions of some few which were either new creations or comparatively undistinguished in the earlier times.
Opis, a town of sufficient magnitude to attract the attention of Herodotus, was situated on the left or east bank of the Tigris, near the point where the Diyaleh or Gyndes joined the main river.

Its position was south of the Gyndes embouchure, and it might be reckoned as lying upon either river.