Irish: Lá Fhéile Pádraig, "the Day of the Festival of Patrick"), is a cultural and religious holiday celebrated annually on 17 March, the death date of the most commonly-recognised patron saint of Ireland, Saint Patrick (c. AD 385–461).
Who was St. Patrick?
St. Patrick, the patron saint of Ireland, is one of Christianity’s most widely known figures. But for all his celebrity, his life remains somewhat of a mystery. Many of the stories traditionally associated with St. Patrick, including the famous account of his banishing all the snakes from Ireland, are false, the products of hundreds of years of exaggerated storytelling.
- It is known that St. Patrick was born in Britain to wealthy parents near the end of the fourth century. He is believed to have died on March 17, around 460 A.D.
- The mythology surrounding his life became ever more ingrained in the Irish culture: Perhaps the most well known legend is that he explained the Holy Trinity (Father, Son and Holy Spirit) using the three leaves of a native Irish clover, the shamrock.
History of St. Patrick's Day.
The Irish have observed this day as a religious holiday for over 1,000 years. However, the first parade held to honor St. Patrick’s Day took place not in Ireland but in the United States. On March 17, 1762, Irish soldiers serving in the English military marched through New York City. Along with their music, the parade helped the soldiers reconnect with their Irish roots, as well as with fellow Irishmen serving in the English army.
THE CHICAGO RIVER ON ST. PATRICK’S DAY
As Irish immigrants spread out over the United States, other cities developed their own traditions. One of these is Chicago’s annual dyeing of the Chicago River green. The practice started in 1962, when city pollution-control workers used dyes to trace illegal sewage discharges and realized that the green dye might provide a unique way to celebrate the holiday.
ST. PATRICK’S DAY AROUND THE WORLD
Today, people of all backgrounds celebrate St. Patrick’s Day, especially throughout the United States, Canada and Australia. Although North America is home to the largest productions, St. Patrick’s Day is celebrated in many other locations far from Ireland, including Japan, Singapore and Russia.
Sydney, Australia 
Munich, Germany
New York, USA 
Moscow, Russia
Disneyland Paris, France
ST. PATRICK’S DAY TRADITIONS
THE SHAMROCK
The shamrock, which was also called the “seamroy” by the Celts, was a sacred plant in ancient Ireland because it symbolized the rebirth of spring. By the seventeenth century, the shamrock had become a symbol of emerging Irish nationalism. As the English began to seize Irish land and make laws against the use of the Irish language and the practice of Catholicism, many Irish began to wear the shamrock as a symbol of their pride in their heritage and their displeasure with English rule.
IRISH MUSIC
Music is often associated with St. Patrick’s Day. From ancient days of the Celts, music has always been an important part of Irish life. The Celts had an oral culture, where religion, legend and history were passed from one generation to the next by way of stories and songs.
CORNED BEEF
Each year, thousands of Irish Americans gather with their loved ones on St. Patrick’s Day to share a “traditional” meal of corned beef and cabbage. Though cabbage has long been an Irish food, corned beef only began to be associated with St. Patrick’s Day at the turn of the century.
THE LEPRECHAUN
The original Irish name for these figures of folklore is “lobaircin,” meaning “small-bodied fellow.”
Belief in leprechauns probably stems from Celtic belief in fairies, tiny men and women who could use their magical powers to serve good or evil. In Celtic folktales, leprechauns were cranky souls, responsible for mending the shoes of the other fairies.
Here's a clip of the latest St. Patrick's Day parade in Dublin:
