II. Historical Setting, Authorship, and Date of Esther
Assuming that Esther was the Queen of Xerxes I (486-465 b.c.), the first banquet would be dated 483-482 b.c. (1:3-4), and Esther made queen in December 479 or January 478 b.c. (2:16-17). The next date (3:7) would be April 17, 474 B.C., and the next date (3:13) would be March 7, 473 b.c. The decree (8:9) was written June 25, 474 b.c.
The book does not name its author. Since it has no indications of Greek influence on vocabulary or customs, it seems best to keep the date of the book between 465 and 333 b.c.