The Babylonians already knew how to make wooden pillars or columns, probably covered with metal, and made use of them in lighter architecture, as for instance the
Tile construction presents necessarily a certain monotony which is here accentuated by the absence of windows. To relieve this monotony, glazing, colouring, or woodwork were resorted to, in case the use of columns was excluded; sometimes more artistic measures were used, such as projecting pilasters, which in Chaldea were somewhat crude, but richly ornamented in Assyria; also mosaics of conical form, or decorations of vases on the walls. The upper stones of the walls were decorated with battlements. The inner, as well as the outer walls, had a stone covering up to a certain height, and higher up a polychromatic layer of stucco. Ivory, and particularly bronze decorations, were much employed. In spite of all this, the impression given by Babylonian and Assyrian buildings is one of massiveness, almost clumsiness, and the decorations seem childish, paltry, and commonplace. Hence also the disproportion of length and breadth, in other words the elongated form of the rooms, whose roof not being supported by columns, had to rest on the side walls, and whose breadth depended on the length of the roof beams.
On the other hand, the almost exclusive use of tiles had this advantageous result, that it was almost imperative to make prodigal use of arch and vault construction. That the Chaldaic architects were the inventors of these constructions, with which the Etruscans were formerly erroneously credited, cannot be positively affirmed, for they are also found in Egypt, although seldom made use of there. Without doubt, however, the Babylonians and Assyrians developed them greatly and knew how to make use of them with great skill. From the false arch, which is formed by allowing each succeeding layer of stone to project over the foregoing one, to the finished arch, all kinds are represented by them. Not only were all underground canals and sewers, vaults of masonry, but all gateways ended in arches, and even the ceilings of some apartments, particularly those in the part of the palaces which seems to have been the harem were wholly or partially vaulted.
The Babylonians and Assyrians have built extensively many and great cities enclosed within mighty walls, extended palaces and peculiar temples. They cannot be enumerated here or even described in general terms.
A few important points, however, may be touched upon. In the first place it must be noticed that, while in Egypt the monumental buildings were tombs and temples, in Babylon and Asshur they were mainly palaces. Although no pains nor expense were spared in the erection of the temples, they were smaller than the palaces, of which they were in some cases certainly annexes.