From Wikipedia (for whatever that is worth)
Purim (/ˈpʊərɪm/; פּוּרִים Pūrīmⓘ, lit. ‘lots’; see Name below) is a Jewish holiday that commemorates the saving of the Jewish people from annihilation at the hands of an official of the Achaemenid Empire named Haman, as it is recounted in the Book of Esther (usually dated to the 5th century BCE).
I prefer the VeggieTales version. https://www.youtube.com/watch?v=JyMpbGYR-0A