Charles Ellicott Commentary Esther 1:11

"to bring Vashti the queen before the king with the crown royal, to show the peoples and the princes her beauty; for she was fair to look on." — Esther 1:11 (ASV)

To bring Vashti. —It is evident from the way in which the incident is introduced that had Ahasuerus been sober he would not have asked such a thing. Vashti naturally sends a refusal.

Crown royal. —If this were like that worn by a king, it would be a tall cap decked with gems, and with a linen fillet of blue and white; this last was the diadem. (See Trench, New Testament Synonyms, § 23.)