Even the roman catholic church acknowleges the pagan origin of easter....

The word Easter, which comes from the Anglo-Saxon, is a term derived from the pagan goddess of the dawn. - The Catholic Encyclopedia, Revised and Updated, Copyright 1987, Robert C. Broderick, Editor, Thomas Nelson Publishers.

Another thing, anyone who has studied the Bible knows that the crucifixion and resurrection happen during the Jewish festival of the Passover, which began on the 14th of Nisan in the Jewish calendar. For millennia the Jews have observed this festival week of Passover & Feast of Unleaven Bread beginning on the 14th of Nisan. Since Jesus died on the 14th of Nisan, then the resurrection happened on the 16th of Nisan.
If your birthday is on the 16th the actual day varies year to year, its not on Tuesday every single year just because you may have been born on Tuesday.
Why then if its truly a commemoration of the ressurection does Easter always fall on sunday???