A people of unknown origin who entered Mesopotamia from the east, across the Zagros mountains. They spoke a language that is not related to any other known language. It is only poorly known from a few phrases and personal names in cuneiform documents. The Kassites were first mentioned by the Babylonian king Samsiiluna (reigned 1749–1712), and they appear with some frequency as a menace to the rural population in many Old Babylonian royal inscriptions. They penetrated into Mesopotamia and were concentrated in the region around Sippar. Many Kassites remained tribally organized even when they became sedentary. When the Hittite king Mursili I raided Babylon and thus terminated the First Dynasty of Babylon, a Kassite ruling elite achieved power over northern Mesopotamia, which was gradually extended to include the whole country with the victory over the Sealand by Ulam-Buriash in c. 1595 (see KASSITE DYNASTY). When the Kassite Dynasty came to an end in c. 1155, the Kassites continued to live as a distinct group in Mesopotamia. Some occupied important posts in subsequent kingdoms, while the tribal groups in the eastern hills were still feared as a warlike people at the time of Alexander’s conquest.
Historical Dictionary of Mesopotamia. EdwART. 2012.