The legend of Saint Patrick is irresistibly captivating-he drove the snakes out of Ireland, battled the druids, and used the three-leaf Shamrock to convert the pagan Irish to belief in the Christian Trinity. Yet, as so often happens, these stories are mere myths that fold under closer scrutiny. Snakes never plagued the Irish countryside, and the Emerald Isle's most beloved saint wasn't even Irish but a Briton of the Roman nobility. Fortunately, the...