Albert Barnes Commentary Esther 1:9

"Also Vashti the queen made a feast for the women in the royal house which belonged to king Ahasuerus." — Esther 1:9 (ASV)

Vashti - If Ahasuerus is Xerxes, Vashti would be Amestris, whom the Greeks regarded as the only legitimate wife of that monarch, and who was certainly married to him before he ascended the throne. The name may be explained either as a corruption of Amestris, or as a title, vahishta, (Sanskrit: vasishtha, the superlative of vasu, “sweet”); and it may be supposed that the disgrace recorded (Esther 1:19–21, see the note) was only temporary; Amestris in the later part of Xerxes’ reign recovering her former dignity.