St. Patrick's Day is a great American story.

• Position: Your Life

From dyeing the Chicago (Ill.) River green to the annual parade in Boston, Mass., St. Patrick's Day has become an American tradition where everyone is Irish. However, our annual March celebrations were born from the painful experiences of early Irish immigrants, many of whom were Catholic.

"Irish immigrants to America had a very difficult story in the 19th and early 20th century," says Mary McCain, Irish Studies instructor at Chicago's DePaul University. "Even as far back as the American Revolution, Catholics were viewed with deep suspicion, especially because the Catholic Church is not a democracy. In addition, most Irish immigrants were poor. Having grown up on farms, most did not have skills that translated to the large urban areas they were migrating to."

McCain notes that Irish immigrants began holding parades on St. Patrick's Day as a celebration of their culture and a rallying cry for fellow immigrants. "These early immigrants, by having their parades, were saying, 'We're here: we're staying: and we're going to make our way in this country.' Jump to 2014 and we see people wearing buttons saying, 'Kiss me, I'm Irish.' Being Irish has become something to celebrate. It's a great American story."

In a strange turn of events, St. Patrick's Day celebrations in Ireland have been influenced by those in the U.S. St. Patrick's Day long has been a public holiday in Ireland, but traditionally was a much quieter affair, "Families would get together for a meal, many attended mass, and that was the extent of it," relates McCain.

"The new Irish Free State had military parades on March 17 starting in the 1920s, but it's only been in the last 20 years or so that it's become the St. Patrick's Day Festival, a multi-day event more along the lines of our big cities' celebrations here in the U.S. In fact, most of the publicly festive traditions were imported from--and heavily influenced by--big cities in America."

St. Patrick's Day is marked on March 17 to commemorate the anniversary of St. Patrick's death. "St. Patrick played a huge role in spreading Christianity to Ireland in the fifth century. Christianity reached Ireland pretty early on and, while St. Patrick was probably not...