`That beats Banagher'
I only recently heard the origin of the famous saying, "That beats Banagher". In complete form, of course, it goes: "That beats Banagher, and Banagher beats the devil."
Banagher is a parish in County Derry, about 20 miles from the city of Derry, and in this parish repose the remains of Saint Muros O'Heney, its patron saint. He is buried in a sand mound graveyard attached to Banagher Old Church, which he built, and, according to authorities, he died about the middle of the 12th century. He was regarded by the people as a man of great sanctity, and they held that a handful of sand from his grave was able to overcome all evil - even the devil himself. Thus the saying arose that "Banagher (sand) beat the devil".
At first the sand was used for spiritual purposes only, but in due course of time was desecrated by being used for all and every purpose. I cannot really say whether it is still used or not. In any case, I understand, that is the origin of the phase, which is no longer confined even to Ireland, but used all over the world as an exclamation of surprise.
The Irish Times, July 16th, 1931