St. Patrick's Day is best known for parades, beer, and turning rivers green, but the holiday has a long history that's more somber than its current incarnation.
St. Patrick was born around 387 C.E. in Scotland, and turned to God once he was kidnapped by slave traders and brought to Ireland to be a shepherd.
Saint Patrick journeying to Tara
"The love of God and his fear grew in me more and more, as did the faith, and my soul was rosed, so that, in a single day, I have said as many as a hundred prayers and in the night, nearly the same," he wrote, according to Catholic Online. "I prayed in the woods and on the mountain, even before dawn. I felt no hurt from the snow or ice or rain."
He joined the priesthood after his escape at the age of twenty, and eventually became a bishop. Patrick was tasked with the mission of bringing Christianity to Ireland, where he was enormously successful in converting much of the mainly Druid and pagan population.
St. Patrick's Day originated as a Roman Catholic holiday recognizing St. Patrick, and was brought to America by Irish immigrants as a way of affirming their identity. It's since been adopted by Americans of all backgrounds.
A members of the Catamount Pipe Band, from Montpelier, Vt., left, blows her bagpipes while marching in a St. Patrick's Day Parade, in Boston's South Boston neighborhood, Sunday, March 17, 2013
Some Catholics celebrate St. Patrick's feast day by going to mass, while other observers of the holiday wear orange and green and eat cabbage and corned beef. Lots of beer drinking may also be involved, particularly Guinness. St. Patrick's Day parades are commonly held in many cities.
Deirdre Kelly, left, Linda Forth, second from left, Darren McCarthy, center, and Eimear Ni Bhriain, of Dublin, Ireland, cheer on the marchers during the 251st annual St. Patrick's Day Parade, Saturday, March 17, 2012 in New York
The shamrock is associated with St. Patrick, as he reportedly used the three-leafed plant as a way of explaining the Trinity- Father, Son, and Holy Spirit.
A man dressed as St. Patrick rides on a float in the annual St. Patrick's Day Parade in Boston, Sunday, March 18, 2012.