Megilat ester, the book of Esther, is not a romantic novel. It is an historical document (=igeret) which records one of the most dangerous events in the history of the Jewish people: when we all were at the verge of extermination.
What makes Megilat Esther a very special book is that in spite of being an historical document, it is not written as a dry prose, like the historical documents authored by Herodotus at about the same time (ca. 450 BCE). Megilat Esther is also a masterpiece of literature. It is written with a supreme literally style: a sophisticated textual structure, intrigue, irony, and tension that sometimes borders with vertigo. In addition, Megilat Esther might be classified as a book of musar (=Jewish behavioral psychology) in that it generously describes the mental processes and profiles of its main characters, particularly the dysfunctional personalities of the Megila's villains.
But before we discuss all these aspects of the Megila let us begin with the historical background of Megilat Esther.
In the first verse, the book of Esther provides the references of time and space:
(i) The tradition of Persian Jews, passed throughout the generations until our days is that the King Achashverosh was the Persian emperor Khashayar-Sha. And Khasayar-Sha is not other than the famous King Xerxes, who reigned in the Achaemenid Persian dynasty between 486 to 465 BCE. This time coincides with the Jewish time-reference mentioned in the Megila: Mordekhay was the son or Ya-ir, who was the son of Shim'i, who was the son of Qish, who was exiled at the time of Yekhonya (Jeconiah) the king of Yehuda (ca.597. This time is different in Seder Olam. For the full discussion see Mitchell First's book here).
(ii) Achashverosh's Kingdom extended from India to Qush (today Sudan/Ethiopia, in those days Nubia). The Persian Empire consisted of 127 "city-states" and it was the largest Empire that ever existed in the history of humankind!
From the story of Purim
by Shira Cohen-Regev, from Aish.com