Ahasuerus Scripture - Esther 3:7

In the first month, that [is], the month Nisan, in the twelfth year of king Ahasuerus, they cast Pur, that [is], the lot, before Haman from day to day, and from month to month, [to] the twelfth [month], that [is], the month Adar.

Link: https://bible-history.com/studybible/Esther/3/