Ahasuerus
Ahasuerus is the Persian king who is the protagonist of the Book of Esther.
Overview
Modern authors generally identify Ahasuerus with Xerses I. Ancient sources rather refer to him as Artaxerses (Artaxerses I, Artaxerses II, or Artaxerses III). The identification with other Persian kings has also been suggested.
It does not seem however that the author of the Book of Esther aimed to refer to any particular historical character. In the fictitious narrative (as well as in other ancient Jewish sources) Ahasuerus is simply the generic name given to the "King of Persia."