Vashti (English Wikipedia)

Browning, W. R. F., ed. (2009), "Ahasuerus", A Dictionary of the Bible (2nd ed.), Oxford University Press, doi:10.1093/acref/9780199543984.001.0001, ISBN 978-0-19-954398-4, retrieved 2020-04-17, The story is fictitious and written to provide an account of the origin of the feast of Purim; the book contains no references to the known historical events of the reign of Xerxes.
Tucker, Gene M. (2004) [1993], Metzger, Bruce M.; Coogan, Michael D. (eds.), "Esther, The Book of", The Oxford Companion to the Bible, Oxford University Press, doi:10.1093/acref/9780195046458.001.0001, ISBN 978-0-19-504645-8, retrieved 2020-04-17, Although the details of its setting are entirely plausible and the story may even have some basis in actual events, in terms of literary genre the book is not history.
Littman, Robert J. (1975). "The Religious Policy of Xerxes and the "Book of Esther"". The Jewish Quarterly Review. 65 (3): 146. doi:10.2307/1454354. JSTOR 1454354. Xerxes could not have wed a Jewess because this was contrary to the practices of Persian monarchs who married only into one of the seven leading Persian families. History records that Xerxes was married to Amestris, not Vashti or Esther. There is no historical record of a personage known as Esther, or a queen called Vashti or a vizier Haman, or a high placed courtier Mordecai. Mordecai was said to have been among the exiles deported from Jerusalem by Nebuchadnezzar, but that deportation occurred 112 years before Xerxes became king.

jewishencyclopedia.com (Global: 1,019^th place; English: 784^th place)

Littman, Robert J. (1975). "The Religious Policy of Xerxes and the "Book of Esther"". The Jewish Quarterly Review. 65 (3): 146. doi:10.2307/1454354. JSTOR 1454354. Xerxes could not have wed a Jewess because this was contrary to the practices of Persian monarchs who married only into one of the seven leading Persian families. History records that Xerxes was married to Amestris, not Vashti or Esther. There is no historical record of a personage known as Esther, or a queen called Vashti or a vizier Haman, or a high placed courtier Mordecai. Mordecai was said to have been among the exiles deported from Jerusalem by Nebuchadnezzar, but that deportation occurred 112 years before Xerxes became king.
"The Religious Policy of Xerxes and the 'Book of Esther'", Littman, Robert J., The Jewish Quarterly Review, 65.3, January 1975, p.145–148.

Browning, W. R. F., ed. (2009), "Ahasuerus", A Dictionary of the Bible (2nd ed.), Oxford University Press, doi:10.1093/acref/9780199543984.001.0001, ISBN 978-0-19-954398-4, retrieved 2020-04-17, The story is fictitious and written to provide an account of the origin of the feast of Purim; the book contains no references to the known historical events of the reign of Xerxes.
Tucker, Gene M. (2004) [1993], Metzger, Bruce M.; Coogan, Michael D. (eds.), "Esther, The Book of", The Oxford Companion to the Bible, Oxford University Press, doi:10.1093/acref/9780195046458.001.0001, ISBN 978-0-19-504645-8, retrieved 2020-04-17, Although the details of its setting are entirely plausible and the story may even have some basis in actual events, in terms of literary genre the book is not history.