This enumeration of tributary lands shows these kings to have been good warriors. For a hundred years before the end of the Kassite dynasty, the kingdom of Assyria, founded before 3000 B.C. in all probability, was growing in strength and importance. When the Babylonians were unable to hold out against invading kings, naturally the Assyrians felt in no way bound to render the tribute they had paid Babylonia to usurping foreigners, and took advantage of the occasion to assert their sovereignty. As has been previously noted, the Assyrians were of pure Semitic stock, and, as their own artists represent them, apparently had not intermarried with the Chaldeans, as the Semites farther south had done. They were warlike in disposition, and knew neither the luxuries of the southern state nor its enervating climate. They had even become powerful enough to make treaties with the rulers of Babylon regarding disputed lands, and this fact in itself was significant. For some considerable period after the invasion of the Kassites, Assyria was concerned with her own affairs, but the time was coming when she would make her power felt in the mother country. Generally speaking, the Kassite rule was an age of peace. Among the Tell el Amarna letters, unearthed upon the ancient site of the "Horizon of the Sun's Disk," correspondence has been found between some of these Asiatic rulers and the kings of Egypt. The letters open with the preliminaries customary in oriental correspondence: "To Kadashman-Bel, king of Kardunyash, my brother; thus saith Amenophis, the great king, the king of Egypt, thy brother: with me it is well. May it be well with thee, with thy house, with thy wives, with thy children, with thy nobles, with thy horses and with thy chariots, and with thy land may it be well; with me may it be well, with my house with my wives, with my children, with my nobles, with my horses, with my chariots, with my troops, and with my land, may it be very well." Regarding this particular letter and others of the same period, Rogers says: "No historical material of great moment is offered in these letters. They reveal a period of relative peace and prosperity, and deal, in considerable measure, with the little courtesies and amenities of life. It is, for example, curious to find the Babylonian king reproving the king of Egypt for not having sent an ambassador to inquire for him when he was ill. When kings had time for such courtesies, and could only excuse themselves for failing to observe them on the ground of their ignorance of the illness, and the great distance to be covered on the journey, there must have been freedom from war and from all distress at home and abroad."[2]