Magical duels between early Christian missionaries and Druids of the British Isles

Saint Patrick magically duels a Druid

In the Roman and post-Roman era; the early Christian missionaries to the British Isles were highly successful at converting the Druidic pagans. 

This may suggest a basic religious compatibility; such that Christianity may have seemed like a natural extension or complement of the Druidic religion. 

For instance; according to Julius Caesar, the Celts of Gaul and Britain seem to have been exceptionally courageous in battle because they did not fear death; being convinced that they would personally survive death in some mode of reincarnation back into this mortal life. 

In a context where personal survival was already an established conviction; the Christian missionaries promise of resurrected eternal life in a Heaven, rather than merely returning to re-live "more-of-the-same", may have been regarded as a significantly better prospect. 

But, even if the post-mortal Christian outcome was better than what Druids could offer; there was the problem of establishing the missionary's authority to promise it. 

After all; why should a Celtic tribal King believe the word of some foreign priest who turned-up at his hall telling a story about the afterlife?  

A Christian missionary would therefore need to establish his own divine authority; and this would usually (it seems) be done by performing "wonders" with divine aid: wonders such as miracles, and also defeating the existing priesthood in trials of spiritual-strength.

This was done to prove the new God was stronger than the old ones, and prove that the new kind of priest spoke with divine authority.   

One such trial of spiritual strength was some variation of the magical duel - analogous to that in the Old Testament (Exodus 7: 8-13) between Aaron and the Pharoah's magical priests - the episode of the magical staffs and the snakes. 

It is important to recognize that the magic of Pharoah's wise Men is depicted as real; but weaker than the magic of Aaron and Moses.

Much the same things were reported in the evangelization of the British Isles, as John Michell summarizes in his 1990 book New light on the ancient mystery of Glastonbury ( pp103-4: I have condensed this passage):   

The great mystery behind early Christianity in Britain is how the first missionaries managed to persuade the chiefs, nobles and Druids to lead their people in converting to the new faith of Christ. Certainly there was opposition, but there is no record of violence or bloodshed. 

Contests between the rival men of religion took place on a professional level, as trials between rival magicians. We only hear about those engagements where Christians won, but it appears that their magic was generally superior to that of their opponents. 

Thus St Patrick prevailed over the Druids of Tara, St Columba defeated the Druids of Bruidh, and St David won a contest with the magician Boia. 

In times when the outcomes of battles were largely determined by the powers of the Druids on each side, a compelling inducement to accept Christianity was that Christian magic proved more effective than that of the pagans.  

The arts of ancient magic are no longer known and it is impossible to say by what combinations of psychology, conjuring, weather control, and elemental invocation; prehistoric battles were conducted. 

It is clear, however, that (unlike Christian magic) the magic of tribal shamans was ineffectual against outsiders of a different religion.

My understanding is that in ancient times magic was real and powerful, and could (in some civilizations) reliably be deployed as required (for instance, to build the pyramids). 

Nowadays, I think magic is still real, still happens; but evidently it is weaker and much less reliable than in the past. Thus; magic cannot nowadays be commanded in ways that seem to have been normal (at least for suitable gifted and trained persons) in Biblical times, or in the early centuries AD.

Nonetheless; it seems only honest to recognize that (bowdlerisations aside) early Christians used magic, as well as other types of miracle, to establish their credentials as speaking with authority on behalf of Jesus. 

Indeed; the remarkable effectiveness of early British missionaries (including those who later became Saints) was sometimes due precisely to the greater effectiveness of the new Christian magic, as compared with the old magic of rival pagan priests.