Why does the date of Easter change every year, while most other celebrations are celebrated on the same day? Answer: Every feast is celebrated at a certain time for a reason. Saints feast days are commonly the day of their death. While we don’t know Jesus’ exact birthday, we celebrate the “light of the world” around the time of winter solstice, as dark, wintery days begin to lengthen again. We have a historical clue, however, to when the Easter events occurred. We know that Jesus was crucified the day before Passover. The Jews calculated the date for Passover based on both the solar and lunar calendars. It corresponds to the first full moon after the spring equinox. The early Christians maintained this connection in their celebrations of Easter on the first Sunday after the paschal full moon. We don’t re-calculate the full moon every year. As astronomy developed, so too did the forecasts of when Easter would occur in future years. The Church has created a table of calculated dates, projecting the date of Easter decades in advance. The date of Easter also determines the date of Ash Wednesday and the season of Lent, as well as the feast days following in the Easter season, including Pentecost. So these feasts move, too! This tradition may seem complicated, but it connects our Christian faith now to what has come before — our Jewish roots and the real, historical reality of Christ’s suffering, death, and resurrection.