The essential feature of the temple within the enclosure was the sanctuary of the deity to whom the temple was dedicated, around which were grouped chambers for the service of the priests in connection with the ritual. Entrance to this Holy of Holies and its subsidiary cells was through a _hypostyle hall_, so called because its ceiling of slabs of stone was supported upon stone beams that rested upon columns. The latter, to withstand the weight of the superincumbent mass, were of great girth and closely ranged, so that an effect as of the depths of a forest was produced, rendered more mysterious and apparently limitless by the dim and fitful light. This penetrated through _clerestory_ windows, covered with pierced stonework and set in the sides of the central portion of the roof, which, supported on higher columns, rose above the side roofs, as the nave of a Gothic cathedral rises above the level of the aisles. When one recollects that the interior was completely covered with symbolic ornament and pictures, one can imagine no mode of lighting better adapted to produce a phantasy of effect, to preclude distinctness of vistas and promote a suggestion of limitless immensity, according with the idea of the eternal continuity of the soul’s existence, on which the religion of the Egyptians was founded. The only approximation in architecture to the mysterious grandeur of the hypostyle hall, leading to the sanctuary, is the nave and aisles and choir of a Gothic cathedral. But the latter presents a great difference, since it was arranged for the congregational service of crowds of worshippers and, partly for this reason and partly because it was a product of the comparatively sunless north, it is flooded through its numerous and large stained-glass windows more abundantly with “dim religious light.” It remains to note the approach to this hall through an open court which was surrounded on two or three sides by a colonnade or peristyle, while an avenue of columns frequently led through the centre from the main entrance of the pylons to the portal of the hall. This combination of Court, Hall, and Sanctuary with its Chambers, already present in the =Ramesseum=, formed the essential of every temple plan, even during the period of Roman occupation. But while the nucleus of the plan was organically complete, unity of effect was abandoned in actual practice owing to the additions made to the original temple by successive kings, who would contribute another hall of columns or another court and sometimes erect another temple as an annex. The most remarkable example of this gradual accretion of additional features is to be found at Karnak; a group of temples in honour of the Sun-god Ra-Ammon, the building of which extended throughout the period of the New Empire.