To appreciate the motives which impelled Assyria from time to time to intervene in Babylonian politics, and to attempt spasmodically a southward expansion, it would be necessary to trace out her own history, and note the manner in which her ambition in other quarters reacted upon her policy in the south. As that would be out of place in the present volume, it will suffice here to summarize events so far as Babylon was affected. The friendly attitude of Puzur-Ashur to Burna-Buriash was maintained by the more powerful Assyrian king Ashur-uballit, who cemented an alliance between the two countries by giving Burna-Buriash his daughter Muballitat-Sherûa in marriage. On the death of Burna-Buriash, his son Kara-indash II., who was Ashur-uballit's grandson, ascended the throne, and it was probably due to his Assyrian sympathies that the Kassite party in Babylon revolted, slew him and set Nazi-bugash in his place. Ashur-uballit invaded Babylonia, and having taken vengeance on Nazi-bugash, put Kurigalzu III., another son of Burna-Buriash, upon the throne.[53] But the young Kurigalzu did not fulfil the expectations of his Assyrian relatives, for after Ashur-uballit's death he took the initiative against Assyria,[54] and was defeated at Sugagi on the Zabzallat by Enlil-nirari, to whom he was obliged to cede territory. A further extension of Assyrian territory was secured by Adad-nirari I., when he defeated Kurigalzu's son and successor, Nazi-maruttash, at Kâr-Ishtar in the frontier district of Akarsallu.[55] We have already seen from the Boghaz Keui correspondence how the Hittite Empire and Babylon were drawn together at this time by dread of their common foe, doubtless in consequence of the aggressive policy of Shalmaneser I. We do not know whether Kadashman-Enlil II. followed the promptings of Khattusil, and it is not until the reign of Kashtiliash II.[56] that we have record of fresh conflicts. Then it was that Babylon suffered her first serious disaster at Assyrian hands. Up to this time we have seen that two Assyrian kings had defeated Babylonian armies, and had exacted cessions of territory as the result of their victories. Tukulti-Ninib I. was only following in their steps when he in turn defeated Kashtiliash. But his achievement differed from theirs in degree, for he succeeded in capturing Babylon itself, deported the Babylonian king, and, instead of merely acquiring a fresh strip of territory, he subdued Karduniash[57] and administered it as a province of his kingdom till his death.[58] The revolts which closed Tukulti-Ninib's reign and life[59] were soon followed by Babylon's only successful campaign against Assyria.