Easter is a pagan fertility celebration. If you google "Ishtar" read her story. Basically, it mirrors Jesus' death and resurrection word for word. When a religion is growing, it's not uncommon for them to adopt celebrations from other religions to make transition easy. Kind of like "Oh, you celebrate Mithra's birthday on December 25th? Well, that's Jesus' birthday!"
Jesus, if the bible is to be believed, couldn't have been born in December based on a lot of readings. So, Mithra (and a few other "messiahs") were born on December 25th.
It doesn't discount the holidays themselves, but it's always irksome to hear shouts that you need to keep Christ in Christmas, when the date and celebration as a whole (gifts and big meals are pagan too) come from other places.