The Paschal Triduum is the apex of the entire liturgical calendar, and I hope readers of this post had the opportunity to enjoy as many celebrations and commemorations during Holy Week as possible. I’m sometimes asked what the best book or video is to give to someone who is interested in the Catholic faith. My response is usually this: If someone wants to know about the Catholic faith, advise that person to free his or her calendar from the evening of Holy Thursday to Easter Sunday morning, and spend as much time in liturgical services as possible. It helps if the seeker is accompanied by a friend with a solid knowledge of the faith, but the liturgy itself does the real evangelizing.
Another question I’m occasionally asked during this time of year is why Passover doesn’t always align with Easter, and why Easter frequently doesn’t align between Western Christians (e.g., Catholic) and Eastern Christians (e.g., Orthodox). The answer lies in that great gift we inherited from our Jewish ancestors: the liturgical calendar. The calendar is a daily reminder that God – in particular through the Incarnation, Passion, and Resurrection of His Son – has sanctified time. He has entered into time, space, and history in order to redeem fallen humanity. And this process of calling people to Himself begins with Abraham, Isaac, Jacob, and all of Israel.
But in commemorating events like the Passover on her calendar (see Ex 12:2), Israel adopted the form of calculating days that was prevalent in the ancient near East, i.e., a lunisolar calendar. One notices this most readily by the fact that Shabbat, i.e., the Sabbath, begins every week at sundown on Friday. From the Christian perspective, one notices this by the claim that Christ rose from the dead on the third day. He was crucified before sundown on Friday (day 1), he “descended into hell” between sundown Friday to sundown Saturday (day 2), and rose from the dead between sundown Saturday and sundown Sunday (day 3). In the decades following the birth of Christianity, as the composition of Church became more Gentile than Jewish, the calendar which the Church adopted in order to commemorate her liturgical celebrations was based on the Roman (solar) calculation of days; though a sense of the Jewish (lunar) day remains with us in the form of Vigil Masses.
At a certain point in early Church history, since Jews and Christians were no longer on the same calendar, it made sense from a Christian perspective to calculate Easter independently of the Hebrew calendar. In fact, while the writing of the Nicene Creed is the most notable achievement of the first Ecumenical Council of the Church, another issue which the Council of Nicaea I (325) addressed was the calculation of the date of Easter. The Council determined that Easter should be celebrated on the first Sunday after the first full moon after the Spring (vernal) equinox; thereby tying the date of Easter to the movements of the sun and moon rather than to the Hebrew calendar. So that should have been that. Problem solved, and that’s why Easter seldom coincides with Passover. But wait, there’s more.
Without going into all of the details – for example, the Wikipedia page on the calculation of the date of Easter is absolutely mind-blowing – two additional factors account for why Western and Eastern Christians have different dates for Easter. First, during the 16th century Renaissance in Western Europe, progress was made on refining the accuracy of the calendar – e.g., this was when the leap year was established – and the previous Roman calendar, known as the Julian after Julius Caesar, was replaced by Pope Gregory XIII in favor of the Gregorian calendar; the one we use today. This change did not effect Eastern Christianity, whose liturgical calendar remains Julian rather than Gregorian. But this subtle refining of calendars would not have been enough, in itself, to alter significantly the dates for Easter between East and West. In addition to this change, how the East and West calculate the first full moon after the vernal equinox accounts for the difference. How can that be, you ask? Well, in the West, the vernal equinox is what it is, and always falls on either March 20th or 21st of the Gregorian calendar. In the East, however, they “fixed” the vernal equinox to March 21st of the Julian calendar. Thus, in the East, the “vernal equinox” may not be on the vernal equinox, resulting in a different calculation for Easter than in the West. The result is that, in the East, Easter always falls between April 4th and May 8th, whereas in the West, it always falls between March 22nd and April 25th.
Lastly, there’s one other factor contributing to the difference of Easter dates between the East and the West. When, after calculations are made, Easter falls on Passover, the Eastern churches move Easter to the following Sunday. As we know from this most recent celebration of Easter, that custom is not shared in the West. Easter and Passover can, and sometimes do, align in the West, but they never do in the East. From the Orthodox perspective, this liturgical tradition is a way of emphasizing that Christ is the fulfillment of the covenant between God and Israel. From my own Catholic perspective, I very much relish when Easter falls on Passover. When this occurs, I think, Jesus’ connection with, and embodiment of, the first Passover becomes all the more real and apparent. “Christ, our Paschal Lamb, has been sacrificed” (1 Cor 5:7). Just as God liberated the Israelites from the bondage of Egypt, by his Passion and Resurrection, Jesus liberates us from the bondage of sin and death. And just as God freed the Israelites out of a love for his people, so too does Jesus free us out of his great love for us. “Now just before the Passover, when Jesus knew that his hour had come to depart out of this world to the Father, having loved his own who were in the world, he loved them to the end” (Jn 13:1). And Jesus calls us to live out his love for us by loving one another. “Love one another; even as I have loved you […]. By this all men will know that you are my disciples, if you have love for one another” (Jn 13:34-5).