Vashti (an Elamite name, possibly related to "thread" in Hebrew or "beautiful" in Persian) is mentioned in the Book of Esther a book included in the Hebrew Bible and Old Testament.

She is often cited as the wife of king Xerxes I of Persia (known by the Persians as "Khshayarsha"). The text transliterates the king's name as Aḥashverosh, rendered into Greek as Ahasuerus.

According to the commentaries of the Midrash she was deposed from royalty, because she refused to obey the King's request that she "show off her beauty" (which is interpreted to "appear naked" or, "dance") in the banquet hall of the palace of "Shushan" Susa which was formerly the capital of Elam.

Her refusal to obey her husband has helped to secure her stature as a folk hero of the modern feminist movement.

She is part of the story behind the Jewish holiday of Purim one of Judaism's festivals. Her position was superceded by Esther, the reputed saviour of ancient Persia's Jews, who was as Ahasuerus's next queen.

According to the Midrash, Vashti was the great-granddaughter of King Nebuchadnezzar II of Babylon. Herodotus, (who tells a similar story with different characters and settings) refers to Xerxes and "Amestris" who is usually ascribed to be the same personnage as Vashti.

Reference:

• The Oxford Bible Commentary (edited by John Barton and John Muddiman, NY: Oxford University Press, 2001, pages 326-327, written by Carol Meyers)
  
• Asimov's Guide to the Bible, Random House, 1969

Hebrew Bible references