AHASUERUS (old Pers. Khshayârshâ).—The Persian king (b.c. 485–465) known to Greek history as Xerxes. Complaints against the Jews were addressed to him (Ezr_4:6). It is he who figures in the Book of Esther; Dan_9:1 erroneously makes him father of Darius the Mede, confusing the latter with Darius Hystaspis, the father of Xerxes. The Ahasuerus of Tob_14:15 is Cyaxares.