Saint Patrick's Day is March 17, the date of his (supposed) death. Tradition is that Leprechauns wear green. If you do not wear green, you risk getting pinched. Green is invisible to Leprechauns.
Saint Patrick, known as the "
Apostle of Ireland" and patron saint of Ireland, was a Christian missionary during the 5th century AD.
At about age 16 he was captured by Irish pirates raiding Britain and made a slave tending animals. After six years he escaped and returned to his family. He became a cleric and returned to his place of captivity as a missionary.