Albert Barnes 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 the queen - This command, though contrary to Persian customs, is not out of harmony with the character of Xerxes; and is evidently presented as something strange and unusual. Otherwise, the queen would not have refused to come.