The conflict, once begun, continues, as has been indicated, with varying fortunes. Occasional breathing spells are brought about by a temporary agreement of peace between the two empires, until at the end of the twelfth century, Assyria, under Tiglathpileser I., secures control over the Babylonian empire. Her kings add to their long list of titles that of 'ruler of Babylonia.' They either take the government of the south into their hands or exercise the privilege of appointing a governor of their choice to regulate the affairs of the Euphrates Valley. From this time on, the history of Babylonia and Assyria may be viewed under a single aspect. The third period of Babylonian history--the second of Assyrian history--thus begins about 1100 B.C., and continues till the fall of Assyria in the year 606 B.C. These five centuries represent the most glorious epoch of the united Mesopotamian empire. During this time, Assyria rises to the height of an all-embracing power. With far greater success than Egypt, she securely established her sovereignty over the lands bordering on the Mediterranean. After severe struggles, the Hittites are overcome, the names of their strongholds on the Orontes changed, in order to emphasize their complete possession by the Assyrians, and the principalities of Northern Syria become tributary to Assyria. Phoenicia and the kingdom of Israel are conquered, while the southern kingdom of Judah purchases a mere shadow of independence by complete submission to the conditions imposed by the great and irresistible monarchy. Far to the northeast Assyria extends her sway, while Babylonia, though occasionally aroused to a resistance of the tyrannical bonds laid upon her, only to be still further weakened, retains a distinctive existence chiefly in name. The culture of the south is the heritage bequeathed by old Babylonia to the north. Babylonian temples become the models for Assyrian architecture. The literary treasures in the archives of the sacred cities of the south are copied by the scribes of the Assyrian kings, and placed in the palaces of the latter. Meanwhile, the capital of Assyria moves towards the north. Ashur gives way under the glorious reign of Ashurnasirbal to Calah, which becomes the capitol in the year 880 B.C.; and Calah, in turn, yields to Nineveh, which becomes, from the time of Tiglathpileser II., in the middle of the eighth century, the center of the great kingdom. Under Ashurbanabal, who rules from 668 to 626 B.C., the climax of Assyrian power is reached. He carries his arms to the banks of the Nile, and succeeds in realizing the dreams of his ancestors of a direct control over the affairs of Egypt. A patron of science and literature, as so many great conquerors, Ashurbanabal succeeds in making Nineveh a literary as well as a military center.