Saint Patrick’s Day (Irish: Lá Fhéile Pádraig) is a yearly holiday celebrated on 17 March.It is named after Saint Patrick (circa AD 387–493), the most commonly recognized of the patron saints of Ireland. It began as a purely Christian holiday and became an official feast day in the early 1600s. However, it has gradually become more of a secular celebration of Ireland’s culture. It is a public holiday on the island of Ireland; including Northern Ireland and the Republic of Ireland. It is also widely celebrated in places where there are large numbers of Irish immigrants and their offspring – this includes Great Britain, Canada, the United States, Argentina, Australia, New Zealand and Montserrat, among others.

Chicago River on St. Pat's

Wearing of green

According to legend, Saint Patrick used the shamrock, a three-leaved plant, to explain the Holy Trinity to the pre-Christian Irish people.

Originally the color associated with Saint Patrick was blue, not, in fact, green.[2] However over the years the color green and its association with Saint Patrick’s day grew. Green ribbons and shamrocks were worn in celebration of St Patrick’s Day as early as the 17th century.[3] He is said to have used the shamrock, a three-leaved plant, to explain the Holy Trinity to the pre-Christian Irish, and the wearing and display of shamrocks and shamrock-inspired designs have become a ubiquitous feature of the day.[4][5] Then in 1798 in hopes of making a political statement Irish soldiers wore full green uniforms on 17 March in hopes of catching attention with their unusual fashion gimmick.[2] The phrase “the wearing of the green”, meaning to wear a shamrock on one’s clothing, derives from the song of the same name.

In the United States

The north White House fountain was dyed green in celebration of Saint Patrick’s Day on 17 March, 2009.

Early celebrations

Irish Society of Boston organized what was not only the first Saint Patrick’s Day Parade in the colonies but the first recorded Saint Patrick’s Day Parade in the world on 18 March 1737.[27][unreliable source?] The first parade in Ireland was not until the 1931 parade in Dublin. This parade in Boston involved Irish immigrant workers marching to make a political statement about how they were not happy with their low social status and their inability to obtain jobs in America. New York’s first Saint Patrick’s Day Parade was held on 17 March 1762 by Irish soldiers in the British Army.The first celebration of Saint Patrick’s Day in New York City was held at the Crown and Thistle Tavern in 1766, the parades were held as political and social statements because the Irish immigrants were being treated unfairly.[28] In 1780, General George Washington, who commanded soldiers of Irish descent in the Continental Army, allowed his troops a holiday on 17 March “as an act of solidarity with the Irish in their fight for independence.”[29][30] This event became known as The St. Patrick’s Day Encampment of 1780.[27][unreliable source?] Irish patriotism in New York City continued to soar and the parade in New York City continued to grow. Irish aid societies were created like Friendly Sons of St. Patrick and the Hibernian Society and they marched in the parades too. Finally when many of these aid societies joined forces in 1848 the parade became not only the largest parade in the United States but one of the largest in the world.[31] Courtesy of Wikipedia:  http://en.wikipedia.org/wiki/Saint_Patrick’s_Day