The Paschal Controversy centred on the dating of Easter. The controversy had become quite serious in the second century when the Quadtrodeciman heretics were excommunicated. This group celebrated Easter on Jewish Passover.
Easter is so important that all Christians, no matter where they are in the world, would celebrate Easter at the same time. The dating of Easter was also a matter of some practical importance.
It was important that the date, which marked the celebration of the Passion, Death and Resurrection of Jesus, should somehow keep assoication with the date of the Jewish Passover, which, for Christians, marked the occasion of Jesus' death. The Jews calculated this by lunar months rather than solar calenders months. Passover was always on the 14th of the month of Nisan, which was the day of the full moon in the first Lunar month of Spring.
Christian communities each developed their own Paschal Tables for calculaing the date of Easter. The Council of Arles met in 314 and declared that Easter must be celebrated on the same day throughout the world. In 325 the Council of Nicea declared that Easter must be celebrated on the same Sunday throughout the Christian world.
The Paschal cycles of the Alexandrian Churchs was based on a cycle of 19 years. The church in the West devised tables based on a cycle of 84 years. Victorius of Aquitaine drew up his table to be a cycle of 532 years. This system was adopted in the West and remained in Gaul until the 8th century.
The 84 year cycle was the one that was probably brought to Ireland by both Palladius and Patrick. It remained in use there and became known as the 'Celtic 84'. In 577 the Victorian calender calculated Easter as falling on April 18; and the Spanish church computed an Easter date of 21 March.
In 597, Gregory of Tours complained that he was celebrating a Latin Easter while people around him were celebrating the Greek.
It was during the late 6th or 7th century that the greatest difference emerged between the Celtic date for Easter and that on which Easter fell elsewhere. Also at this time, the Celtic monks embarked on the peregrinatio. There was conflict with the local clergy.
Meeting with Augustine
In Britain, conflict only arose with the convergence of the mission of the Celts and the Roman mission of Augustine. Augustine, a monk from Marseilles, was appointed by Pope Gregory the Great to undertake a mission to pagan Anglo-Saxon England. He had given him authority over the bishops, ordering him to "correct the obstinate."
In 602 Augustine held a conference with the "bishops and teachers of the English people", at a place which became known to Bede as Augustine's Oak. Augustine in an attempt to assert Roman authority did not rise to greet them when they arrived. The Celtic monks were offended at what they took to be both a lack of respect and arrogance.
Columbanus had also fallen into conflict over the Celtic method of dating Easter. In 600 he wrote to Pope Gregory on the matter and also to his successor Sabinian. He was summoned to a meeting with the French bishops in 603 to address the issue.
Appeal, Synod at Mag Lene and Letter
In 605, Laurentius of Canterbury "came to realise that in Ireland as well as in Britain, the life and profession of the people was not in accordance with church practice in many things". He wrote a circular letter to the Irish bishops and abbots, outling the Roman arguement on the dating of Easter. In 628 Pope Honorius wrote to "the nation of the Scots" whom he saw as few in number, and living "at the ends of the earth". He appealed to them not to consider themselves wiser than all other Churches regarding the dating of Easter.
In 629-30 a Synod at Mag Lene, near Durrow, seriously considered accepting Roman practices. One abbot, Fintan, from the northern part of Ireland, whom Cummian refers to as a "whited wall" challenged the decison. As a result, a deputation was sent to Rome to clarify some issues. It returned in 632 completely convinced of the rightness of Roman practices.
In 632/3 Cummian sent a letter to Segene, abbot of Iona, presenting the Roman point of view. His main fear was that of being "cut off from the universal Church"
Southern Ireland and Events at Northumbrian
By 636 Roman practices had been adopted by the churches in the southern part of Ireland. In 640, Pope John IV wrote to the "doctors and abbots of the Scots", but seems to have wrongly associated them with the Quatrodeciman heresy. "Some of your province, in opposition to the orthodox faith, are striving to revive a new heresy out of an old".
In England there was relatively little strife over the Easter question and things had remained as they had been left at Augustine's Oak. However, events were to come to a head when the dispute entered the Northumbrian royal household. King Oswy of Northumbria had been brought up with Celtic practices and had married the princess Eanfled who herself was devoted to Roman practices.
This would have caused great inconvience in the royal household as well as confusion among the Christians of the kingdom. Aldfrith, the kings son, held the sub-kingdom of Deira and was ambitious to rule over all of Northumbria. He saw the opportunity to weaken his fathers influence and so he wanted to conquer the kingdom. He felt sure his father would retain his Celtic usages and so his power would diminish as a result. Oswy held the Synod of Whitby in 664.