Kassites, a people of ancient times who ruled Babylonia for more than 400 years. They probably came from what is now Iran. The Kassites began migrating into Mesopotamia after 2000 B.C. and became rulers at Babylon after that city had been sacked by Hittites in 1595 B.C. In the mid-13th century B.C. the Kassites lost control of Babylonia to the Assyrians. The Kassites soon regained control but in the 12th century were overthrown by the Elamites.