It was when Cyrus had become master of Western Asia that the Persians began to think of building the famous palaces at Persepolis, Susa, and Pasargadæ. Most of these palaces and the tombs were built of a close-grained limestone that is found very plentiful in the mountainous country of Persia. The royal tombs were, as a rule, cut out of the living limestone rock (Fig. 242). They are of the time of Darius, and are all of one type that seems to have been invented by one mind, and, after the first was cut, _speos_-like, out of the native rock—probably that of Darius itself—the rest were copied faithfully from it. The great height from the ground of the tomb itself was arranged for safety from violation. The sculptured figure of the king is represented near the top, in the act of worshipping the sacred fire seen on the right; at the centre of the top of the field is seen the emblem of the god Ahurâ-Mazda and the sun disk (Fig. 243). An older form of tomb, the “built” tomb, is seen at the right of the rock-cut tombs, and a larger illustration of this rectangular cemetery is seen at Fig. 244. The latter type of tomb belongs to the time of Cyrus. We must not look for much in the way of religious architecture in Ancient Persia. Where temples in other countries were required, fire-altars took their place in Persia (Fig. 245). These altars, by reason of their uses, were generally found in “high places,” on summits of hills and on rocks. [Illustration: Fig. 245.—Fire Altars, Naksh-i-Rustem. (F.C.) (P. & C.)] The fire-altars at Naksh-i-Rustem are really one with the rock on which they stand. Remains of a fire-temple have been discovered at Ferûz-abad, which is supposed to have had a roof; but the ends of the temple would be open, with the sacred hearth on the top and centre of a lofty flight of steps, on a quadrangular plan. [Illustration: Fig. 246.—Persepolis; Staircase of the Palace of Darius. (D.) (P. & C.)] [Illustration: Fig. 247.—Fragment of a Door-Frame from a Hypostyle Hall, Sausa. (D.) (P. & C.)] The buildings in Persia of the Achæmenidæ Dynasty, both palaces and tombs, are of the pillar and beam, or the architrave system of construction. The horizontal ceilings were of wood, and were panelled very elaborately, and rested on stone supports. The doorways and windows are square-headed, upholding a lintel (Fig. 248). [Illustration: Face and Profile of Principle Doorways. Face and Profile of Lateral Doorways. Profile of Window. Face of Cornice. Profile of Niche. Fig. 248.—Elevations and Sections of Doorways and Windows of a Palace at Persepolis. (F.C.) (P. & C.) ] [Illustration: Fig. 249.—Persepolis, Doorway to Royal Tomb. (D.) (P. & C.)]