Easter is the celebration of the pagan goddess Eostre which is why I assumed the early Christians chose this time for their celebration of death and ressurection as most Christian festivals were placed on or near Pagan celebrations.
But it also falls around the Jewish passover which is now taken to celebrate the mythical delivery of the Jewish people from slavery in Egypt.
The actual passover story is the killing of non Jewish children by the angel of god. The angel "Passed over" the houses of Jews who had smeared goats blood on the door lintel of their houses.
An appalling thing to celebrate in my opinion but don't say it too loudly as you are accused of antisemitism for virtually nothing these days.