St. Patrick's Day falls on March 17, which is traditionally thought to be the day of his death, although that is probably a guess. For centuries, St. Patrick's Day was simply a religious holiday, celebrated in church rather than at the pub; in fact, in Ireland pubs were closed on March 17 until the 1970s.
It was not until Irish immigrants began coming to America that St. Patrick's Day took off as the international, secular celebration we know today. Boston's Charitable Irish Society held the first St. Patrick's Day parade in 1737. Irish New Yorkers first marched in 1762, and Philadelphia caught on in 1780. For early Irish-Americans, the holiday was a way of looking back fondly on the old country and expressing ethnic pride, and over the years more and more people have joined in the fun. The Irish themselves recently adopted many American traditions surrounding St. Patrick's Day, largely as a ploy to attract tourists.
What would St. Patrick think of the way his holiday is celebrated today? "He would probably be astounded," says Freeman. "He was not the sort of man who liked to draw attention to himself, and he would not have been comfortable with all the parades and the drinking. I think he would be very surprised."