St. Patrick's Day, that is… From Michael Grynbaum and Nikita Stewart, "Amid Mayoral Missteps, Irish Eyes Are Rolling in New York City", NYT 3/16/2014:
Correction: March 17, 2014
An earlier version of this article misquoted a comment from Malachy McCourt on St. Patrick. Mr. McCourt said, “My attitude is, St. Patrick banished the snakes from Ireland and they all came here and they became conservatives.” He did not say St. Patrick banished the slaves from Ireland.
In fact, slavery was legal in Ireland (as in the rest of the British Empire) until 1833, a millennium and a half after St. Patrick's time. Though as a slave himself for six years, he might have favored abolition, if the concept had ever come to his mind.