The tendency of the platform mounds, as soon as formed, must have been to settle down, to bulge at the sides and become uneven at the top, to burst their stone or brick facings and precipitated them into the ditch below, at the same time disarranging and breaking up the brick pavements which covered their surface.

The weight of the buildings raised upon the monads must have tended to hasten these catastrophes, while the unsteadiness of their foundations and the character of their composition must have soon had the effect of throwing the buildings themselves into disorder, of loosening the slabs from the walls, causing the enamelled bricks to start from their places, the colossal bulls and lions to lean over, and the roofs to become shattered and fall in.

The fact that the earlier palaces were to a great extent dismantled by the later kings is perhaps to be attributed, not so much to a barbarous resolve that they would destroy the memorials of a former and a hostile dynasty, as to the circumstance that the more ancient buildings had fallen into decay and ceased to be habitable.

The rapid succession of palaces, the fact that, at any rate from Sargon downwards, each monarch raises a residence, or residences, for himself, is yet more indicative of the rapid deterioration and dilapidation (so to speak) of the great edifices.
Probably a palace began to show unmistakable symptoms of decay and to become an unpleasant residence at the end of some twenty-five or thirty years from the date of its completion; effective repairs were, by the very nature of the case, almost impossible; and it was at once easier and more to the credit of the monarch that he should raise a fresh platform and build himself a fresh dwelling than that he should devote his efforts to keeping in a comfortable condition the crumbling habitation of his predecessor.
It is surprising that, under these circumstances, a new style of architecture did not arise.

The Assyrians were not, like the Babylonians, compelled by the nature of the country in which they lived to use brick as their chief building material.