Saint Patrick's Day has come to be associated with a few ideas and symbols tied to IrelandIrish: anything green and gold, shamrocks and luck. In the United States and many other nations, the first widespread Saint Patrick's Day celebrations were organized by Irish immigrants in celebration and recognition of their culture.
To those who celebrate its intended religious meaning, St. Patrick's Day is a traditional day for spiritual renewal and offering prayers for missionaries worldwide. The Irish are descendants of the ancient Celts, but the Vikings, Normans and English contributed to the ethnic nature of the people. Centuries of English rule largely eliminated the use of the ancient Gaelic, or Irish, language. Most Irish are either Catholics or Protestants (Anglicans, members of the Church of England).
So, why is it celebrated on March 17? One theory is that that is the day that St. Patrick died. Since the holiday began in Ireland, it is believed that as the Irish spread out around the world, they took with them their history and celebrations. The biggest observance of all is, of course, in Ireland. With the exception of restaurants and pubs, almost all businesses close on March 17. Being a religious holiday as well, many Irish attend mass, where March 17 is the traditional day for offering prayers for missionaries worldwide before the serious celebrating begins.
In American cities with a large Irish population, St. Patrick's Day has become a very big deal. Big cities and small towns alike celebrate with parades, "wearing of the green," music and songs, Irish food and drink, and activities for kids such as crafts, coloring and games. Chicago, for example, even dyes its river green.