It has been observed that the original Chaldaean monarchy lasted, under various dynasties from about B.C. 2400 to B.C. 1300, when it was destroyed by the Assyrians, who became masters of Babylonia under the first Tiglathi-Nin, and governed it for a short time from their own capital. Unable, however, to maintain this unity very long, they appear to have set up in the country an Assyrian dynasty, over which they claimed and sometimes exercised a kind of suzerainty, but which was practically independent and managed both the external and internal affairs of the kingdom at its pleasure. The first king of this dynasty concerning whom we have any information is a Nebuchadnezzar, who was contemporary with the Assyrian monarch Asshur-ris-ilim, and made two attacks upon his territories. The first of these was by the way of the Diyaleh and the outlying Zagros hills, the line taken by the great Persian military road in later times. The second was directly across the plain. If we are to believe the Assyrian historian who gives an account of the campaigns, both attacks were repulsed, and after his second failure the Babylonian monarch fled away into his own country hastily. We may perhaps suspect that a Babylonian writer would have told a different story. At any rate Asshur-ris-ilim was content to defend his own territories and did not attempt to retaliate upon his assailant. It was not till late in the reign of his son and successor, Tiglath-Pileser I., that any attempt was made to punish the Babylonians for their audacity. Then, however, that monarch invaded the southern kingdom, which had passed into the hands of a king named Merodach-iddin-akhi, probably a son of Nebuchadnezzar. After two years of fighting, in which he took Eurri-Galzu (Akkerkuf), the two Sipparas, Opis, and even Babylon itself, Tiglath-Pileser retired, satisfied apparently with his victories; but the Babylonian monarch was neither subdued nor daunted. Hanging on the rear of the retreating force, he harassed it by cutting off its baggage, and in this way he became possessed of certain Assyrian idols, which he carried away as trophies to Babylon. War continued between the two countries during the ensuing reigns of Merodach-shapik-ziri in Babylon and Asshur-bil-kala in Assyria, but with no important successes, so far as appears, on either side.