St. Patrick, as much as any historical facts about him can be pinned down, was thought have been enslaved in the 5th century and taken to Ireland (circa 403 CE). After regaining his freedom (and becoming re-enslaved in French, then re-regaining his freedom), he ultimately became a missionary to Ireland where he is widely credited with ending slavery in that country. Thomas Cahill writes of Patrick, that he was "the first human being in the history of the world to speak out unequivocally against slavery" (Cahill 114).

St. Patrick is quoted as writing in his Confessions: "It is the custom of the Christians of Rome and Gaul to send holy men, fitted for the office, with much gold, to the Franks and the other heathen nations, to redeem those captives who are Christians. You slay them, and sell them to strange nations, who know not God. .... there free-born Christians are sold, and made the slaves especially of those most wicked, detestable, and apostate Picts" (Morris 124), so he can be credited with denouncing the practice of slavery.