1. St. Patrick of Ireland is one of the world's most popular saints. He was born in Roman Britain and when he was fourteen or so, he was captured by Irish pirates during a raiding party and taken to Ireland as a slave to herd and tend sheep.
2. St. Patrick's given name at birth was Maewyn Succat. When he became a priest, he changed his name to Patricius, from the Latin term meaning "father figure."
3. The very first St. Patrick's Day parade was not in Ireland. It was in Boston in 1737.
4. Erin go Bragh translates to "Ireland forever."
5. One of the longest-running and largest St Patrick's Day parades in North America occurs each year in Montreal. The yearly celebration has been organised by the United Irish Societies of Montreal since 1929. The parade has been held yearly without interruption since 1824. St Patrick's Day itself, however, has been celebrated in Montreal since as far back as 1759 by Irish soldiers in the Montreal Garrison following the British conquest of New France.
6. The largest parade in the United States, held since 1762, is in New York City, and draws more than one million spectators each year.
7. The city of Chicago goes so far to celebrate that they dye their river green.
8. Green is associated with Saint Patrick's Day because it is the color of spring, of Ireland, and of the shamrock.
9. Green has not always been the color associated with St. Patrick and St. Patrick's Day. The Order of St. Patrick, established in 1783, selected blue as its color because dark green was already taken. Green became popular with the 1798 Irish Rebellion when wearing a clover on a lapel became a sign.
10. On St Patrick's Day it is customary to wear shamrocks and/or green clothing or accessories (the "wearing of the green"). St Patrick is said to have used the shamrock, a three-leaved plant, to explain the Holy Trinity.
11. In 1948 President Truman became the first president to attend a St. Patrick’s Day parade.
12. St. Patrick is a hero in Ireland. And there are about 60 churches and cathedrals named for him in Ireland alone. One of the most famous cathedrals is St. Patrick's Cathedral in Dublin. These grounds bear the mark of the place where St. Patrick baptized his converts
13. According to the most recent census data, 33.3 million U.S. residents claim Irish ancestry, which is seven times Ireland's total population.
Saint Patrick's Day is celebrated in more countries than any other national festival.