Two centuries later we learn from Tiglath-pileser I. that Moschians and Hittites had overrun part of this Assyrian territory, and occupied some of the Assyrian settlements. Once more, therefore, the Assyrian troops marched to the north-west; the provinces which lay in the valley of the Murad-chai were recovered, and the old province of Subari cleared of intruders. Soon afterwards Tiglath-pileser forced his way into Southern Cappadocia and the valley of the Sarus, making Comana tributary, razing to the ground the fortresses that had resisted him, and erecting on their site chambers of brick, with bronze tablets on which his conquests were recorded. Eastern Cilicia was known at the time to the Assyrians as Muzri, or “the Marchland,” a clear proof that it had long formed a borderland and debatable territory between the Assyrian Empire and the nations of Asia Minor. It is thus evident that even before the rise of the Assyrian monarchy, the road that led to the mining districts of Cappadocia, along the valleys of the Upper Tigris, Euphrates and Tokhma Su, was not only known to the Assyro-Babylonians, but had actually constituted Assyrian territory, which was colonized by Assyrian garrisons and paid tribute to Nineveh whenever Assyria was strong enough to enforce its authority. At the eastern extremity of the road stood the city of unknown name, now represented by “the Burnt Mound” of Kara Eyuk, whose existence as an Assyro-Babylonian city probably dates back to the age of Khammu-rabi. It was the outpost of Babylonian culture in Asia Minor. Babylonian art, and, above all, the Babylonian system of writing, were brought by it into the heart of the Hittite region, and the archæological objects found there consequently become important for chronological dating. Not far off, on the other side of the Halys, rose the Hittite capital, now known as Boghaz Keui, the centre from which, as Professor Ramsay has shown,[142] the early roads of Asia Minor radiated in all directions. Boghaz Keui is being excavated at the present moment. Hundreds of clay tablets have already been found there, inscribed with cuneiform characters, the majority of which are in the native Hittite language, though many are in Semitic Babylonian, including a copy of the famous treaty between Ramses II. and the Hittite king. So far as the tablets have been examined, they show that the Hittite empire extended from the west of Asia Minor to the Egyptian frontier, and that the cuneiform characters were used in ordinary life. [Illustration: THE RUINS AT BOGHAZ KEUI.]