Ahasuerus (a-hăs-u-ç'rus), lion-king, the name of one Median and two Persian kings mentioned in the Old Testament. 1. In Daniel 9:1 Ahasuerus is said to be the father of Darius the Mede. The first Ahasuerus is Cyaxares, the conqueror of Nineveh, b.c. 634. 2. The Ahasuerus, king of Persia, referred to in Ezra 4:6, must be Cambyses, thought to be Cyrus' successor, and perhaps bis son. b.c. 529. 3. The third is the Ahasuerus of the Book of Esther. This Ahasuerus is probably Xerxes of history, Esther 1:1, b.c. 485, and this conclusion is favored by the resemblance of character and by certain chronological indications, the accounts of his life and character agreeing with the book of Esther. In the third year of Ahasuerus was held a great feast and assembly in Shushan the palace, Esther 1:3, following a council held to consider the invasion of Greece. He divorced his queen Vashti for refusing to appear in public at this banquet, and married, four years afterwards, the Jewess Esther, cousin and ward of Mordecai. Five years after this, Hainan, one of his counsellors, having been slighted by Mordecai, prevailed upon the king to order the destruction of all the Jews in the empire. But before the day appointed for the massacre, Esther and Mordecai induced the king to put Haman to death, and to give the Jews the right of self-defence.