The Kassites formed the military aristocracy of Babylonia, which was called Karduniash, for nearly six centuries.  Agum II was the first of their kings who became thoroughly Babylonianized, and although he still gave recognition to Shuqamuna, the Kassite god of battle, he re-exalted Merodach, whose statue he had taken back from “Khani”, and decorated E-sagila with gifts of gold, jewels, rare woods, frescoes, and pictorial tiles; he also re-endowed the priesthood.  During the reign of his successor, Burnaburiash I, the Dynasty of Sealand came to an end.

Little is known regarding the relations between Elam and Babylonia during the Kassite period.  If the Kassite invaders crossed the Tigris soon after the raid of the Mitannian Hittites they must have previously overrun a great part of Elam, but strongly situated Susa may have for a time withstood their attacks.  At first the Kassites held northern Babylonia only, while the ancient Sumerian area was dominated by the Sealand power, which had gradually regained strength during the closing years of the Hammurabi Dynasty.  No doubt many northern Babylonian refugees reinforced its army.

The Elamites, or perhaps the Kassites of Elam, appear to have made frequent attacks on southern Babylonia.  At length Ea-gamil, king of Sealand, invaded Elam with purpose, no doubt, to shatter the power of his restless enemies.  He was either met there, however, by an army from Babylon, or his country was invaded during his absence.  Prince Ulamburiash, son of Burnaburiash I, defeated Ea-gamil and brought to an end the Sealand Dynasty which had been founded by Ilu-ma-ilu, the contemporary and enemy of Samsu-la-ilu, son of Hammurabi.  Ulamburiash is referred to on a mace-head which was discovered at Babylon as “king of Sealand”, and he probably succeeded his father at the capital.  The whole of Babylonia thus came under Kassite sway.

Agum III, a grandson of Ulamburiash, found it necessary, however, to invade Sealand, which must therefore have revolted.  It was probably a centre of discontent during the whole period of Kassite ascendancy.

After a long obscure interval we reach the period when the Hyksos power was broken in Egypt, that is, after 1580 B.C.  The great Western Asiatic kingdoms at the time were the Hittite, the Mitannian, the Assyrian, and the Babylonian (Kassite).  Between 1557 B.C. and 1501 B.C.  Thothmes I of Egypt was asserting his sway over part of Syria.  Many years elapsed, however, before Thothmes III, who died in 1447 B.C., established firmly, after waging a long war of conquest, the supremacy of Egypt between the Euphrates and the Mediterranean coast as far north as the borders of Asia Minor.