St. Patrick's Day – Celebrating the Green
St. Patrick is believed to have driven the snakes from Ireland. Once a pagan himself, St. Patrick is one of Christianity's most widely known figures.
The modern secular holiday is based on the original Christian saint's feast day also thought to be the date of the saint's death. In 1737, Irish immigrants to the United States began observing the holiday publicly in Boston and held the first St. Patrick's Day Parade in New York City in 1766.
Today, the tradition continues with people from all walks and heritages by wearing green, eating Irish food, and attending parades. St. Patrick's Day is bursting with folklore; from the shamrock to the leprechaun and to pinching those that are not wearing green.
Courtesy of http://www.history.com/minisites/stpatricksday