A few examples are found of the _peripteral_ type of temple, consisting of a _cella_ or sanctuary, surrounded on the four sides by columns. In one instance--the temple erected by Amenophis III at =Elephantine=--the columns are confined to the front and rear, while at the sides are square piers. These structures are small, and, in two cases, at =Philae=, are unaccompanied by a cella; which suggests that they were used as waiting places in connection with the adjoining temples. PTOLEMAIC AND ROMAN PERIODS During the period of political decadence the building of temples declined, but it was renewed under the rule of the Ptolemies and continued during the Roman occupation. While, notwithstanding foreign domination, the Egyptian type was in the main adhered to, an important change of detail was adopted in the manner of lighting the hypostyle hall. The light was admitted from the front, over the top of screen walls, which were erected between the columns to about half their height. A celebrated example is at =Edfou=, the most perfectly preserved temple of this period, which also conforms most closely to the old type. For in other instances there was a growing tendency to introduce novelties of detail, characterised by greater elaboration and ornateness. It is signally represented in the =Temple of Isis= on the island of =Philae=, for here the shape of the site has produced irregularities in the planning of the various buildings, which enhances the general picturesqueness of the whole group. Unfortunately, in consequence of the erection of the Assouan Dam, these temples at =Philae= are submerged for the greater part of the year. How far the Egyptians studied orientation, or the placing of a temple with reference to the points of the compass, is uncertain. But there are grounds for supposing that in some cases they orientated the principal entrance toward the sun or a certain star, the exact position of which on some particular day would indicate to the priests the exact time of year. =Palace and Domestic Architecture.=--Of palace architecture the only conjectured remains are the buildings erected in the rear of the Temple of Karnak by Thothmes III and the pavilion of Medinet Abou on the west bank of the Nile at Thebes; the unsuitability of which as royal residences has already been noted.