Destroyed and rebuilt century after century upon the self-same spot, the _debris_ of these surrounding dwellings so raised the level of the soil, that the temples ended for the most part by being gradually buried in a hollow formed by the artificial elevation of the surrounding city.

Herodotus noticed this at Bubastis, and on examination it is seen to have been the same in many other localities.

At Ombos, at Edfu, at Denderah, the whole city nestled inside the precincts of the divine dwelling.

At El Kab, where the temple temenos formed a separate enclosure within the boundary of the city walls, it served as a sort of donjon, or keep, in which the garrison could seek a last refuge.

At Memphis and at Thebes, there were as many keeps as there were great temples, and these sacred fortresses, each at first standing alone in the midst of houses, were, from the time of the Eighteenth Dynasty, connected each with each by avenues of sphinxes.