Purim is celebrated on the Jewish Calendar Date: 14th of Adar (15th of Adar for cities in the land of Israel that were walled during the First Temple period).
In the years 539-332 BCE the First Persian or Achaemenid Persian Empire ruled from the border of India to Egypt and Turkey. When the Babylonians expelled many of the Jews from the land of Israel in 586 BCE, they dispersed throughout the area ruled by the Babylonian Empire.
According to the Biblical Book of Esther, a senior Persian minister named Haman conspired against the Jews in the 5th-4thcentury BCE. He gained the approval of the Persian Achashverosh Commonly identified as Artaxerxes II, who ruled from 405 to 358 BCE.
It should be noted that there are many scholars who question whether the Book of Esther is meant to be read as an accurate historical account.
To wipe out the Jews and loot their wealth for the kingdom’s treasury. Haman cast a lot or pur to decide which month the deed would be carried out. The lot fell on the month of Adar.
A Jewish Persian Judge named Mordechai and a Jewish Persian queen named Esther intrigued against Haman’s plans and eventually succeeded in causing the King to execute Haman and his family. This seminal event resulted in the Jews gaining the right to organize and defend themselves against those who wished to destroy them. The Jews did so and killed many of their enemies. Thus for the Jews, the month of Adar was a month where the threat of destruction was replaced with salvation.