CIASSARE (in the Bisutūn inscription, Huwašītra = “of good development”). — King of the Medes (635?–584), son of Phraortes, who had died fighting against the Assyrians. In 614 he allied with Nabopolassar (q.v.), king of Babylon, and led the Umman-Manda (“peoples of Manda” = Medes; according to others = Scythians) against the Syrian capital Nineveh, which fell in the month of ’ābh (July–August) of 612. The two allies continued their conquests westward, occupying Assyria, northern Mesopotamia, Armenia, and Cappadocia. Cyaxares also attacked Lydia; but the treaty concluded in 585 between him and Alyattes, king of Lydia, established the Halys River as the boundary between the two kingdoms. He died in 584.
BIBL.: Herodotus, I, 103–106; P. Dhorme, La fin de l’empire assyrien d’après un nouveau document (la «Chronique de Gad»), in Rev. biblique, 33 (1924), pp. 218–34. Gaetano M. Perella