The very heart of the liturgical year—Easter—is a moveable feast. This is how the date of Easter is decided each year. All four Gospels place Jesus' death and Resurrection within the time frame of the celebration of the Jewish Passover. Passover occurs at the first full moon of spring in the Hebrew month named Nisan. (Exodus 12:1-20) Thus, Easter is celebrated on the Sunday after the first full moon of spring. The date of Easter then determines the dates of Ash Wednesday (40 days before Easter), Ascension (40 days after Easter) and Pentecost (50 days after Easter).