Ireland Collects Its First Ever Triple Crown, Defeating Wales in Belfast
March 10, 1894
The first use cited in the Oxford English Dictionary is from Whitaker’s Almanack, 1900 (referring to the 1899 tournament):
“In their last match at Cardiff against Wales, Ireland won by a try to nothing, securing the triple crown with three straight victories as in 1894.”
The Irish victory in 1894 was reported as a Triple Crown by The Irish Times at the time and is possibly the first time the phrase was seen in print.
The phrase Triple Crown is also used in a number of other sports.