Saint Patrick's Day is celebrated on March 17th to honor Saint Patrick, a 5th century priest born in Scotland who introduced Christianity to Ireland. According to legend, Saint Patrick used the three-leaf shamrock to explain the Holy Trinity and drove all the snakes out of Ireland. The Irish celebrate by wearing green, attending parades and festivals featuring music and dancing. Americans also celebrate by dyeing rivers green, parading and drinking beer. Leprechauns are mischievous fairy creatures from Irish folklore believed to possess a pot of gold.