His Own Words Survive, and So Does a Second Missionary

Patrick is unusual among ancient saints in that two texts widely accepted as genuinely his own writing survive, the autobiographical Confessio and a Letter to the soldiers of Coroticus, giving historians a rare direct primary source rather than only later legend built up around a name. Even with this advantage, his story is genuinely complicated by the existence of Palladius, a bishop the historical record shows was sent to minister to the Christians already in Ireland before Patrick's own mission, a documented earlier figure whose work later Irish tradition appears to have folded into Patrick's own legend over time, a proposal often called the Two Patricks theory among historians of the period.

Untangling which missionary achievements belong to which man is not fully resolved and remains a live question in early Irish church history. The best known popular legend, that Patrick drove all the snakes out of Ireland, has no basis in his own writings and is a considerably later addition, and it is also simply not consistent with the natural history of the island, which had no native snakes for him to banish in the first place, leading most scholars to read the story as allegorical, representing the displacement of pagan practice by Christianity rather than describing any literal event Patrick himself claimed.