Our knowledge of Egyptian history is more exact than that of some other ancient nations, because scholars have been able to read Egyptian hieroglyphics for a much longer time than they have read the cuneiform or arrow-headed inscriptions which are found in Assyria, Babylon, and Persia. But we know a great deal about the ruins of Assyria, and especially of the cities of Nineveh and Khorsabad, where there are wonderful architectural remains. [Illustration: FIG. 15.--GATEWAYS IN WALLS OF KHORSABAD.] The walls which surrounded Nineveh are an important part of its ruins. It is said that in the days of the earliest sovereign these walls were one hundred feet high, and so broad that three chariots could drive abreast on their top. This story does not seem unreasonable, for all the years that have passed, and all the dust and deposit of these ages that are collected about the foot of the walls, still leave some places where they are forty-six feet high and from one to two hundred feet wide. The lower portion was of limestone, and the upper of sun-dried bricks; the blocks of stone were neatly hewn out and smoothly polished. The walls surrounded the city, which was so large that one hundred and seventy-five thousand people could live there, and we know that its inhabitants were very numerous. The gates which opened through the walls were surmounted by lofty towers, and it is supposed that shorter towers were built upon the walls between the gateways (Fig. 15). The above plans show the arrangement of gateways which have been excavated. It seems that there were four separate gates, and between them large chambers which may have been used by soldiers or guards. The two outer gates were ornamented by sculptured figures of colossal bulls with human heads and other strange designs; but the inner gates had a plain finish of alabaster slabs. It is thought that arches covered these gateways like some representations of gates which are seen on Assyrian bas-reliefs. Within the gates there is a pavement of large slabs, in which the marks worn by chariot wheels are still plainly seen. [Illustration: FIG. 16.--ENTRANCE TO SMALLER TEMPLE, NIMRUD.]