Language / Why are Happy Easter & Merry Christmas the same in Polish [26]

I did a number of searches on the internet and this site on how to translate Merry Christmas into Polish because according to my parents, one year I wished everyone a Happy Easter instead.

I am confused - Why does Wesołych Świąt translate to both Happy Easter & Merry Christmas?
Thanking you in advace for your insights - dzęnkuje bardzo

Sophia (Zosia)