The most common form of myth about very early saints extols their power over dragons and serpents, and these holy-men were usually credited with defeating or slaying such creatures which, more than any, epitomised evil. After all, it was the serpent that tempted Eve in the Garden of Eden.

The Irish holy man Patrick was the saint who, according to legend, drove every snake out of Ireland. Even if this myth were true, Saint Patrick was not the only early religious figure to possess such powers.

Several regional saints made similar claims. Saint Cado of Brittany is credited with expelling serpents in Gaul; Saint Clement expelled a ferocious serpent from Metz.

The citizens of Paris were freed, by Saint Romain, from the horrors of the monstrous dragon Gargouille (from which the word 'gargoyle' is derived), while Saint Marcel is lauded for driving snakes from the same city. Columcille is said to have driven a monster from the River Ness while Saint Ninian is believed to have cleared parts of Scotland of 'many venomous reptiles'.

Even in Ireland, Saint Patrick is not the only holy man to have had power over snakes. In Glendalough Cathedral, County Wicklow, a stone tablet commemorates the defeating of a terrible water-serpent by Saint Kevin of Wexford and his dog Lupus. Saint Enda is said to have driven snakes from the islands around the Irish coast while Columcille is supposed to have rid Tory Island, off Donegal, of all manners of vermin including rats and snakes. This myth is also associated with ancient heroes such as Murrough, the son of Brian Boru, who was certainly not considered a saint.