The celebration of Easter, the most important feast in Catholicism, was not always uniform across the medieval world. Different regions followed different methods of calculating the date of Easter, leading to conflicts and confusion. In the eighth and ninth centuries, the Carolingian rulers of Western Europe sought to impose a single method of Easter computation, based on the Roman tradition, on their diverse subjects and allies.
In two previous essays, I explored the historical and theological aspects of the Carolingian liturgical reforms in the eighth and ninth centuries. In ‘The Real Presence Controversy: A Clash of Theoogie in the 9th Century‘, I examined the debate on the real presence of Christ in the Eucharist, which was sparked by the changes in the words and form of the sacrament. I explained the main positions and arguments of the different parties involved, such as Paschasius Radbertus, Ratramnus of Corbie, and Rabanus Maurus. I also showed how this debate contributed to the development of doctrine and the doctrine of indefectibility. In ‘How the Carolingian Liturgy Promoted and Preserved Frankish Culture,’ I analyzed how the Carolingian rulers used liturgical reform as a tool to promote and preserve Frankish culture and identity. I traced the history of the reforms from Pepin III to Louis the Pious, and their sources of inspiration, such as the Roman rite and Saint Boniface. I also discussed the reasons for the opposition and resistance to the reforms from some regions and churches, such as Aquitaine and Milan.
In this third essay, I will explore the Carolingian debate about the proper way to celebrate Easter and explain why it was one of the most important controversies in the history of Christianity. Although this debate was more scientific than theological in nature and concerned different methods of calculating the date of Easter, which is based on the lunar cycle and the spring equinox, it also had theological, political, and cultural implications, as it reflected the diversity and unity of the Christian world in the early Middle Ages.
The Origin of the Easter Controversy
The origin of the Easter controversy dates back to the second century, when some Christians followed the Jewish practice of celebrating the Passover on the 14th day of Nisan, regardless of the day of the week, while others celebrated the Resurrection on the Sunday after Passover. The latter practice prevailed and was endorsed by the First Council of Nicaea in 325, which also decreed that Christians should not depend on the Jewish calendar but calculate Easter independently. However, the council did not specify how to do this, and different regions developed their own methods of computation.
One of these methods was the Latercus, an 84-year cycle that fixed Easter to the Sunday, falling in the seven-day period from the 14th to the 20th of Nisan. This method was used by some British and Irish Christians until the seventh century when they adopted the Alexandrian computus, a 19-year cycle that fixed Easter to the Sunday falling in the seven-day period from the 15th to the 21st of Nisan. The Alexandrian computus was more accurate and more widely accepted in the Christian world and was based on astronomical observations and mathematical calculations.
The Contribution of the Carolingians
The Carolingian debate began in the late eighth century when some discrepancies were noticed between the Alexandrian computus and the actual astronomical phenomena. The main reason for this was that the Alexandrian computus assumed a fixed date for the spring equinox (March 21), while in reality, it varied slightly from year to year. Moreover, the Alexandrian computus used a lunar cycle that did not correspond exactly to the real phases of the moon. These errors accumulated over time and caused Easter to drift away from its intended date. Today, the Catholic Church calculates the date of Easter as the first Sunday after the Paschal full moon, which is the first full moon on or after March 21.
The debate involved several scholars and ecclesiastics who tried to correct or improve the Alexandrian computus, or to propose alternative methods. Some of them were:
- Saint Bede (673-735), an English monk and historian who wrote extensively on chronology and astronomy. He criticized the Latercus and defended the Alexandrian computus, but also pointed out some of its errors and suggested some corrections.
- Saint Alcuin (735-804), an English scholar and adviser to Charlemagne. He wrote several letters and treatises on the Easter question, arguing for the superiority of the Alexandrian computus over other methods, such as those proposed by Victorius of Aquitaine or Dionysius Exiguus.
- Theodulf (760-821), a Visigothic bishop of Orléans and a poet. He composed a metrical calendar that included a new method of calculating Easter, based on a 532-year cycle that combined solar and lunar cycles. He also wrote a poem in defense of his method, called De ratione paschali. Charlemagne also called upon Theodulf to defend the Filioque clause in the Nicene Creed, which describes the procession of the Holy Spirit from the Father “and from the Son” and which is one of the causes of the division between the Eastern and Roman rite churches. At Charlemagne’s request, Theodulf defended the Filioque clause in his treatise De Spiritu Sancto (“Concerning the Holy Spirit”). It was also at Charlemagne’s urging that Theodulf wrote his treatise on the Sacrament of Baptism, De ordine baptismi (“Concerning the Ordinance of Baptism”).
- Blessed Rabanus Maurus (780-856), a Frankish abbot and archbishop of Mainz. He wrote a commentary on Bede’s works on chronology and astronomy, as well as a treatise on Easter computation, called De computo ecclesiastico. He followed Bede’s corrections to the Alexandrian computus, but also introduced some modifications of his own.
The debate was not only a matter of technical accuracy, but also about promoting various cultural ideas concerning the need for ecclesiastical authority and unity. The Irish missionaries who came to continental Europe in the sixth and seventh centuries often clashed with the local bishops over the date of Easter, as they followed different methods. The most famous example was the dispute between Saint Columbanus and the Synod of Auxerre in 602. Columbanus defended the Latercus as the more ancient and Apostolic tradition, while the Synod insisted on following Rome and the Victorian method.
The Partial Resolution of the Carolingian Easter Debate
The debate was partly resolved by the adoption of the Alexandrian method by most of the Western churches in the eighth and ninth centuries, under the influence of Rome and the Carolingian reformers. The Synod of Whitby in 664 marked the acceptance of the Alexandrian method by the northern English, who had been following the Irish Latercus. The Irish themselves gradually abandoned the Latercus in favor of the Alexandrian method in the early eighth century. However, some regions, such as Aquitaine and Bavaria, continued to use different methods until the late eighth or early ninth century.
The debate also stimulated intellectual and scientific developments in the field of computus, or the science of time reckoning. The Irish scholars were especially renowned for their contributions to computus, as they developed sophisticated mathematical techniques and astronomical observations to calculate Easter and other feasts. They also wrote treatises and commentaries on computus that circulated widely in Europe and influenced later generations of scholars. Some of their works, such as De ratione conputandi (On the Method of Calculation) by Cummianus and De temporum ratione (On the Reckoning of Time) by Bede, are considered classics of medieval science1.
The Carolingian debate did not result in a definitive solution or consensus on how to calculate Easter. It did, however, demonstrate the intellectual vitality and diversity of the Carolingian Renaissance, as well as its interest in preserving and developing the ancient heritage of science and culture. It also showed how Easter computation was not only a technical problem, but also a matter of faith, authority, and identity for Christians in different regions and traditions.
For More Information:
- Chazelle, Celia, The Crucified God in the Carolingian Era: Theology and Art of Christ’s Passion.
- Colish, Marcia L., Carolingian Debates over Nihil and Tenebrae: A Study in Theological Method.
- McKitterick, Rosamond: A Professor of Medieval History at Cambridge University, she has written several papers on the Carolingian era, including “The Carolingians and the written word,” “History and Memory in the Carolingian World”, and “The Frankish church and the Carolingian reforms, 789-895”.
- Ottewill-Soulsby, Sam: He has written on comparative studies in civilizational formation, including the ‘Abbasid and Carolingian Empires.