[….] lightning has always had a special role in the Christian tradition. Seen as one of the instruments of God’s wrath, it was known to the Church Fathers (via the classical tradition) as ‘fire from the heaven’.
St Michael, the Archangel of war, was said to use it. And, across the medieval world, though especially among Celtic-speaking peoples, special shrines were built to Michael with lightning in mind.
Churches or hermitages were dedicated to the Archangel high on cliff-sites or coastal islands with a simple logic. It was there that lightning was most likely to strike and it was there that the hermit could come closest to God’s divine anger.