There are many aspects of the Christian life, from penitence to rejoicing; they cannot all be experienced at once, and none should exclude the others. The church year gives believers an opportunity to experience them all in proper measure. The primary components of the calendar are as follows:

1. Pascha, the Feast of Feasts, the Resurrection of Our Lord and Savior Jesus Christ (known in the West as Easter). The date of Pascha changes every year (falling in April or early May), and the dates of several other feasts (called "movable feasts") are linked to this date.
2. The Twelve Great Feasts, each commemorating an event in the life of the Lord or of His Mother (which are also important events in our salvation). Some of these are "movable" (linked to Pascha) and others are "fixed," occurring on the same calendar date each year.
3. Lesser feasts commemorating the saints of the Church. Most of these are fixed dates.
4. Days and seasons of fasting, most of them linked to one of the feasts.

Great and Holy Pascha

The Date of Pascha

One of the first questions asked by many visitors to the Orthodox Church is, "Why do you celebrate Easter on a different day from Western Christians?" The full answer to this is complex and would require quite a bit of historical background, some of which you can read about here. Briefly, both the Eastern and Western churches calculate the date of Easter based on the first full moon after the vernal equinox. However, the West uses the date of the vernal equinox according to the Gregorian calendar (March 21), while the Orthodox Church uses the date according to the Julian calendar (April 3). (This is true for all Orthodox churches, even those that use the Gregorian calendar for everything else.)

The full answer to this is complex and would require quite a bit of historical background, some of which you can read about here. Briefly, both the Eastern and Western churches calculate the date of Easter based on the first full moon after the vernal equinox. However, the West uses the date of the vernal equinox according to the Gregorian calendar (March 21), while the Orthodox Church uses the date according to the Julian calendar (April 3). (This is true for all Orthodox churches, even those that use the Gregorian calendar for everything else.)

In addition, the Orthodox Church requires that Pascha fall after the Jewish Passover, as Jesus' Resurrection came after the Passover. This is done in order to preserve the significance of Pascha as the fulfillment of the "type" of the Passover. The Passover of the Israelites from Egypt through the Red Sea and eventually into Canaan represents the passage of the Christian from sin through baptism into the Kingdom of heaven. As the blood of the Passover lamb painted on the Hebrews' doorposts in the shape of a cross protected them from the angel of death, so the blood of Christ shed on the Cross preserves us from eternal death.