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8. The Medieval Irish Church: Schism and the Pursuit of Unity

The English Invasion of Britain

After the Roman legions left Britain in 410, a wave of Anglo-Saxon (English) invaders gradually took control, British Christianity and Christians were driven into the western parts of Britain, i.e. Wales. A sixth century British theologian Gildas wrote a scathing attack on the corrupt state of the British church of his day, On the Ruin and Conquest of Britain. Sadly, the British (Welsh) did not seek to Evangelize the pagan English, instead viewing them as the enemy. The conversion of the Germanic pagan conquerors in Britain would come from two sources: Irish missionaries from the monasteries of Ireland and Scotland, and the mission headed by St Augustine sent from Rome in 597. The Irish and Roman missions would eventually come into conflict over the seemingly obscure question of the church’s calendar.

The Great Easter Debate

Debates over the date of Easter go back to the second century, long before Christianity ever reached Ireland. Melito of Sardis (d.180) understood the Christian Pascha (Easter) to coincide with Passover, i.e. it was always celebrated on the 14th day of the lunar month Nisan no matter what day of the week that was. Another tradition that developed was to always celebrate Easter on the first Sunday following the first full moon after the equinox, thereby separating the Christian Pascha from the Jewish Passover.

Agree to Disagree?

In the second century both Pope Anicetus of Rome and Polycarp of Smyrna ensured that the issue did not become a matter of dogma and both sides maintained full communion, though differing on the exact method for calculating Easter’s date. As the second century ended Rome took a stronger position on the issue and Pope Victor I declared the churches of Asia Minor heretical because of their dating method for Easter. Many theologians in the western church, including Irenaeus, disagreed with this dogmatic position and chided Victor for his divisive stance (Eusebius, HE 5.23–25). The ecumenical council of Nicaea (325) ruled the universal church should celebrate Easter on the same day, but failed to produce a method of calculation acceptable to all Christians (Socrates, HE 1.9).

Issues Involved

The differences that later emerged between the Celtic and Roman dates for Easter were primarily over two technical issues, 1) the date of the equinox and 2) the terminal limits for Easter. As early as the fifth century the early Irish church calculated Easter on the basis that the equinox occurred on March 25 and Easter could occur within the limits of lunar 14-20. This method derived from Gaul. It was likely the work of Sulpicius Severus (c. 363-425), whose writings were very influential in the early Irish church. by 541 Gaul had abandoned Celtic-84 in favor of a different system developed by Victorius of Aquitaine. A later system calculated Easter from an equinox of March 21 within the limits of lunar 15-21

An Ecumenical Problem

The problems in producing a single workable Easter dating system for the entire church were immense. No system was without its flaws and there were numerous times when Milan, Spain, Gaul and North Africa all celebrated Easter on different days.

A Theological Problem?

The Easter debate certainly involved issues of national pride and traditionalism. But like most theological disputes its partisans were quick to point out the theological issues involved.

To celebrate Easter on Passover day (Luna 14) was theologically suspect because it meant Christ’s crucifixion must be placed two days before Passover (Luna 12) thereby implicitly denying that Christ is the Passover Lamb (1 Cor 5:7) and that Christ came to fulfill the Law (Matt 5:17, Rom 10:4), thereby denying the historical and theological reliability of NT (or so the argument went). It was also claimed that the authority of local regional churches should be allowed to follow their own traditions on these matters (Columbanus Ep. 3.2).

A counter argument attempted to prove that to claim Easter could be celebrated from March 21 when the equinox was March 25 was a denial that Christ was the light of the world. Irish theologian Columbanus rejected this “dark Easter”, since light has no communion with darkness.” (Ep 1.2-3; citing 2 Cor 6:14).

Outline of the Main Events

  • 597 The Gregorian and Irish missions in England result in the newly established English church using different contradictory Easter dates.

  • 600 Columbanus’ refusal to adopt to the Gallic church’s Easter date causes division and suspicion from the Gallic bishops

  • 605 An Irish bishop Dagan refuses communion with the Roman mission in Kent over the Easter question

  • 605 The Archbishop of Canterbury (Laurence) writes to the Irish church to complain: “we have learned from bishop Dagán who came to [Britain] and from abbot Columbanus in Gaul, that they [the Irish clergy] do not differ from the Britons in their way of life. For when Bishop Dagán came to us he refused to take food, not only with us but even in the very house where we took meals.” (Bede HE 2:4)

  • 628 Pope Honorius writes to the church in Ireland (Bede HE 2:19). Honorius had condemned supposed Quartodecimanism among the Irish (he was mistaken in this). Honorius’ letter is the first time that the Papacy linked the Irish Easter date with heresy.

  • 630 An Irish synod meets near Durrow (Mag-Léna) to discuss the problem

  • 631 An Irish delegation is sent to Rome

  • 632 A local Synod meets at Mag nAilbe in Leinster. A Wexford Abbot, Fintán argues against the “new order which had recently come from Rome” (Honroius’ Letter). A later book called the Life of Fintán (c.800) recounts Fintán’s bold challenge to those supporting Rome’s dating system. A choice of three tests (1) throw copies of the Irish and Roman Easter dating tables into a fire and see which one was preserved through the flames, (2) each side choose a monk to place in a burning house, the survivor would clearly be on God’s side. (3) Raise a holy monk from the dead and ask him which system he supported! The synod was dismissed without reaching a conclusion and didn’t take Fintán up on his three tests. (Corning, 88)

  • 632 The delegation returns from Rome and informs the Irish synod that the Irish Easter date is out of sync with the universal church. The southern churches in Ireland decide to adopt the Roman Easter date. Some northern churches (especially Iona) refuse and kept their old dating system.

  • 633 An Irish theologian (Cummian) writes a treatise to the churches in the north of Ireland calling on them to stop causing division and adopt the new Easter date. He is alarmed that Iona and some of the churches in the north of Ireland can proudly resist the calls to ecclesiastical unity and instead insist, “Rome errs, Jerusalem errs, Alexandria errs, Antioch errs, the whole world errs; the Irish and British alone know what is right.” For Cummian it was simply pride that would prevent any Irish ecclesiastical leader from yielding to the universal celebration of Easter. Who after all were the Irish, asked Cummian, but a “pimple on the face of the earth!”

  • 639 (?) The churches in the north of Ireland write to Rome seeking clarification

  • 640 Pope John writes to the churches in the north of Ireland and accuses the northern Irish churches of heresy (Pelagianism and Quartodecimanism).

  • 664 Synod of Whitby, Northumbria adopts the Roman date. Prior to Whitby’s Synod the most zealous advocate for the Roman Easter date in Northumbria was an Irish cleric called Ronan (Bede, HE 3.25.). The English scholar Wilfrid argues Rome’s case. He would later boast that he had rooted out the poisonous weeds of Irish doctrine at Whitby. The Irish abbot Colman is forced to leave his monastery at Lindisfarne. His immediate successor as bishop of Lindisfarne is an Irish bishop called Tuda who probably came from a southern Irish church that had long adopted the Roman date (Bede, HE 3.26).

  • 703 Adomnán, bishop and abbot of Iona, accepts the Roman date, however, the rest of the monastic community at Iona refuses to accept his decision.

  • 716 Iona finally accepts the Roman date for Easter after an English monk who had trained in Ireland, a man called Egbert, finally convinced Iona to change her tradition in 716 (Bede, HE 5.22)

Synods and the Pursuit of Unity

The Easter dating dispute was the most serious and longest schism in the medieval Irish church. The question that emerged amid the rancour and mutual distrust was how do we deal with disagreements in theology and practice? The Scripture called on Christians “All of you, have unity of mind!” (1 Peter 3:8). But how could unity be preserved?

The early church model was to hold a synod to resolve church conflict (Acts 16). The Early Irish church likewise followed this model. The participants at Irish synods were Bishops, Abbots, and Scholars (Theologians). According to Charles-Edwards, the inclusion of scholars and abbots alongside the bishops was unusual in this early medieval period (ECI, 276). Women and kings not active participants in Irish church synods.

Early Irish Canon Law from 725 (Collectio Canonum Hibernensis) cites a canon from Pope Innocent I (d.417) relating to judging disputed theological questions, the so-called Innocentian canon (not known in any papal document of Innocent), which states that Scripture was the highest court of appeal, followed by the Deutro-canonical books, Church Fathers, Traditions of major Sees, Church history, and the synods of senior ecclesiastics (CCH §19).

Irish theologian Cummian in trying to wrestle with the Easter date controversy in the 630s appealed to Scripture first and then to Patristic sources and finally to a synod. As he wrote in his own words, “Therefore asking the Apostle who says, test everything hold fast to what is good, before I tried it, I did not disdain it. Hence, having cloistered myself for a year and having entered the sanctuary of God (that is sacred Scripture) I studied as much as I was able, then I examined the histories, and finally the cycles which I could find…therefore after a full year (as I said above) in accordance with Deuteronomy, I asked my fathers to make known to me, my elders (that is to say, the successors of our fathers: of Bishop Ailbe, of Ciaran of Clonmacnois, of Brendan, of Nessan, and of Lugid) to tell me what they have thought about our excommunication by the aforementioned Apostolic Sees. Having gathered in Mag Léne, some in person others through representatives sent in their place, they enacted and said: ‘our predecessors enjoined, through capable witnesses (some living, some resting in peace), that we should adopt humbly without doubt better and more valid proofs proffered by the font of our baptism and our wisdom by the successors of the Lord’s Apostles.’ Then they arose in unison and after this, as is our custom, they performed a prayer, that they would celebrate Easter with the Universal Church the next year” (DCP 59, 91-93).

Whereas some in the early Irish church were ready to cut themselves off from those who did not follow their narrow tradition, for others the pursuit of unity was worth fighting for.


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