We know of no Persian queen named Esther, or any Jewish queen of Persia, and we would not expect there to have been one. Queens came from the noble Persian families, not from ethnic minorities. Moreover, real kings don’t choose queens from beauty contests. In fact, Esther enters the story more like a concubine, and only later emerges as a dignified queen. In contrast, Vashti, who was presumably a queen of proper ancestry and clearly in a high position at court, is treated like a concubine by Ahasuerus.