More than 34 million Americans can trace their heritage back to Ireland, according to the U.S. Census Bureau, and many, many more claim to be Irish at least on St. Patrick’s Day. However, how much do you really know about the holiday and the traditions behind it? Below are a few St. Patrick’s Day facts you may not have been aware of:

1. There really was a St. Patrick. He died on March 17 in the year 461 A.D. That’s why we celebrate the feast of St. Patrick on this day.

2. The first St. Patrick’s Day parade was not in Dublin, but in Boston, in 1737.

3. Carnations, sometimes dyed or tinted green, are the traditional flower for St. Patrick’s Day. Other good flowers and plants to give include shamrocks, green orchids and shiny green houseplants like a pathos plant.

4. There are about 10,000 three-leaf clovers for every “lucky” four-leaf clover.

5. More than 100 St. Patrick’s Day parades step off each year around the United States. The largest are in New York City and Boston. The New York City parade draws approximately 200,000 marchers and more than one million spectators each year.

6. Green was once considered an unlucky color in Ireland. The original St. Patrick’s Day color was blue. Green wasn’t adopted until the 19th century.

7. St. Patrick wasn’t Irish. He was born in Britain and kidnapped to Ireland when he was 14 and forced to work as a slave herding sheep. Neither was he originally Catholic. He was a pagan as a child, but embraced Catholicism as a young man. He was eventually made a bishop.

8. The shamrock became associated with St. Patrick’s Day because he used the leaf of this plant to illustrate the concept of the Trinity, the three aspects of God.

9. Although legend maintains that St Patrick drove the snakes out of Ireland, the use of snakes is likely a metaphor for the pagans he converted.