You’ve heard the expression “the luck of the Irish” and
probably thought it meant people from Ireland had “extreme good fortune.” But the phrase originally had a different connotation.
According to Edward T. O’Donnell, an Associate Professor of
History at Holy Cross College and author of 1001 Things Everyone Should Know
About Irish American History, the term is not Irish in origin.
“During the gold and silver rush years in the second half of
the 19th century, a number of the most famous and successful miners
were of Irish and Irish American birth....Over time this association of the
Irish with mining fortunes led to the expression ‘luck of the Irish.’ Of
course, it carried with it a certain tone of derision, as if to say, only be
sheer luck, as opposed to brains, could these fools succeed.”
From www.IrishCentral.com