CIASSARE (in the Bisutun inscription, Huwahítra = “of good development”). — King of the Medes (635?–584), son of Fraortes, who had died fighting against the Assyrians. Having allied himself in 614 Nabopolassar (v.), king of Babylon, C. marched at the head of the Ummam-Manda (“peoples of Manda” = Medes; according to others = Scythians) against the Assyrian capital Nineveh, which fell in the month of ʿabh (July, sixth month) of 612. The two allies continued their conquests westward, occupying Assyria, northern Mesopotamia, Armenia, and Cappadocia. C. also attacked Lydia; but by the treaty concluded in 585 between him and Alyattes, king of Lydia, the river Halys was established 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 « Cronaca di Gadd »), in Rev. biblique, 33 (1924), pp. 218–34. Gaetano M. Perrella