In A.D. 603, Celtic Christians of the British Isles had a vexing problem. Augustine, a Christian missionary, had recently arrived on their shores from Rome and not only condemned some of their Christian practices but demanded they submit to his authority.

In their perplexity, seven British bishops and other learned men consulted a "wise and prudent hermit." Should they abandon their own traditions and submit to the missionary?

"If he is a man of God, follow him," the hermit answered. "If Augustine is meek and lowly in heart, it shows that he bears the yoke of Christ himself, and offers it to you."

The bishops inquired further, "How can we know even this?"

"If he rises courteously as you approach, rest assured that he is the servant of Christ and do as he asks. But if he ignores you and does not rise, then, since you are in the majority, do not comply with his demands."

When the bishops and Augustine met again, Augustine did not rise; the meeting was a failure. The Celtic bishops refused to recognize Augustine as their archbishop, and Augustine prophesied the deaths of the Celtic bishops.

This was definitely a low point in the history of cross-cultural communication, and it illustrates a gap that existed between the Celtic and Roman churches.

The missionary, later known as Augustine of Canterbury (not to be confused with the more famous Augustine of Hippo) had been sent by Pope Gregory I in 596 to convert the pagan Angle and Saxon invaders of Britain. Augustine was prepared for pagans but not for other Christians.

Two centuries earlier, while Goths and Visigoths sacked the continent, Angles and Saxons overran Britain and nearly wiped out the Celtic church in what is now England. Christians were slaughtered, enslaved, or driven to the edges of the British Isles. Communication between the Celts and the rest of the world was broken. The church that remained, primarily in Ireland and Wales, learned to function on its own.

Meanwhile, as the western Roman Empire crumbled under waves of Germanic invaders, the bishop of Rome (the pope) and the church stepped in to fill the power vacuum. Popes such as Leo and Gregory advanced the role of Rome's bishop as supreme authority of all Christendom. With barbarian threats, heresy, and other chaos abounding, uniformity of practice and submission to this uniform authority became crucial—seen as necessary ingredients of godliness.

When the dust of over a hundred years of plunder and conflict settled, communication was reestablished between the Celtic and Roman churches. But by that time, they hardly recognized each other.

Augustine looked on these wild Celtic Christians with suspicion. They acted so differently from civilized people in Rome! He hadn't really wanted to come here in the first place. He felt out of his element in the wilds of Britain. The Celts' unwillingness to submit to his authority looked suspiciously like heresy.

The Celtic Christians, in turn, looked at Augustine apprehensively. They were used to a more independent, less uniform way of organizing church life—hence the monasteries dotting their islands. Unaware of the changes in the wider church world, they were not prepared for these strange new demands and concerns. Hadn't they been faithfully keeping the old customs of the church for centuries? How could it be that they were now in the wrong?

The two groups of Christians went their own ways after this first unsatisfactory encounter. The Celts continued to "stubbornly prefer their own customs to those in universal use among Christian Churches," as the Venerable Bede (the first great English church historian, and writer of the account of the Celts versus the Romans) put it. For the next 60 years, the two sides were able to more or less avoid each other.

When the Celts began missionary work among the English, where Roman missionaries were already working, the two groups met again. The "aberrant" practices of the Celts were painfully obvious to the Romans. Celtic monks shaved their heads so strangely. More significant, Celtic bishops were under the authority of a monastery abbot rather than an archbishop, and Celtic monasteries were semi-autonomous.

And the Celts' method of fixing the date of Easter didn't match the way the rest of Christendom set the date for celebrating this most holy of days.

This Easter tension was perhaps felt most strongly in the royal chambers. King Oswy of Northumbria followed the Celtic method of fixing Easter while his wife, Queen Eanfled, followed the Roman method. Thus it was said that some years, while the king was feasting and keeping Easter, his wife was fasting and keeping Palm Sunday.

The Celts followed one of the oldest methods, using an 84-year calendar. The Romans, however, had adopted a newer method, fleshed out by rigorous church councils. Obviously, the decisions of these councils were not communicated to the Celtic Christians, who inhabited a "corner of a remote island," as they were described by the Romans.

The differences seem trivial to us, but to a church extending its authority to the ends of the earth, they were not. And the Celts were not easily persuaded that Rome's church was preeminent, and that all Christians should be under its authority and rule.

The Roman Christians could finally stand it no longer. They persuaded Oswy to call a meeting in 664 at an abbey in Whitby. The goal was to decide the date to celebrate Easter. Both parties would present their arguments, and King Oswy would decide the matter.

Agilbert, a bishop, and Wilfrid, a priest, represented the Roman church, while the Celts were represented by a rather wild-looking group of men, including two bishops, Colman and Cedd. The account of the Venerable Bede (completed in 731) is the only surviving account of the meeting.

Bishop Colman spoke first: "The Easter customs I observe were taught me by my superiors, who sent me here as a bishop, and all our forefathers, men beloved of God, are known to have observed these customs. And lest anyone condemn or reject them as wrong, it is recorded that they owe their origin to the blessed evangelist Saint John, the disciple especially loved by our Lord, and all the churches over which he presided."

Bishop Wilfrid responded, "Our Easter customs are those that we have seen universally observed in Rome. … We have also seen the same customs generally observed throughout Italy and Gaul. … [and] by men of different nations and languages at one and the same time, in Africa, Asia, Egypt, Greece, and throughout the world wherever the church of Christ has spread. The only people who stupidly contend against the whole world are these Scots and their partners in obstinacy, the Picts and Britons, who inhabit only a portion of these the two uttermost islands of the ocean."

Wilfrid followed up with further insults: "Do you imagine that … a few men in a corner of a remote island are to be preferred before the universal church of Christ throughout the world? And even if your Columba was a saint potent in miracles, can he take precedence before the most blessed Prince of the Apostles, to whom our Lord said: 'Thou art Peter, and upon this rock I will build my Church'?"

When Oswy heard that Peter held the keys to heaven, the debate was over.

"Peter is guardian of the gates of heaven, and I shall not contradict him," the king said. "Otherwise, when I come to the gates of heaven, there may be no one to open them, because he who holds the keys has turned away."

Though most Celts subsequently submitted to the decision, Colman and his followers returned to Iona, where they were still free to continue the traditions of their forefathers. Iona held to their own manner of keeping Easter for another 150 years. A few parts of the Celtic church resisted even longer.

Still, the Synod of Whitby marked a turning point; the differences between the Romans and the Celts could no longer be tolerated. It was only a matter of time before Roman Christianity prevailed in all of the British Isles.

Louise Burton is librarian for Free Lutheran Seminary in Plymouth, Minnesota.