St Patrick's Day is celebrated worldwide on March 17th in honor of St Patrick, the patron saint of Ireland. Born in Britain in the late 4th century, St Patrick was kidnapped and enslaved in Ireland as a teenager, before escaping and later returning to Ireland as a missionary. He is credited with spreading Christianity in Ireland and using the shamrock to explain the Holy Trinity. Today, St Patrick's Day is commemorated with parades, wearing of green clothing, and drinking of green beer, especially in Ireland and areas with large Irish populations like the United States.