Erin go bragh! St Patrick's Day is being celebrated around the world today. But what is the celebration for, and what do we know about the man?
When is St Patrick's Day?
St Patrick's Day is celebrated annually on March 17. The day honours the patron saint of Ireland, but celebrations are held around the world.
Since 1961, St Patrick has also been regarded as a patron saint of Nigeria, a country which is home to around 20 million Catholics.
While many see St Patrick's Day as an excuse to drink endless pints of Guinness while wearing a green wig, there's a little more to it than that.
So who was St Patrick?
St Patrick was a real man who was born in around 385 AD.
He may have been named Maewyn Succat, and changed to Patrick when he later became a bishop. He may be thought of as Irish now, but his exact birthplace is unknown.
It was most likely in England, Wales or Scotland. In his teens, he was captured by pirates and taken to Ireland, where he was put to work as a herdsman.
After six years, he managed to escape and possibly fled back to his home. He became a Christian priest before returning to Ireland as a missionary in the mid fifth century.
He spent the next 30 years establishing schools, churches, and monasteries across the country.
Patrick was later appointed as successor to St Palladius, the first bishop of Ireland. He is said to have died on March 17 in the year 461.
The flag of St Patrick is a red saltire on a white background. The association with Ireland's patron saint dates back to the 1780s, when the Order of St Patrick adopted it as an emblem.
When the 1800 Act of Union (which came into effect from 1 January 1801) joined Great Britain and Ireland, the saltire was added to the British flag to create the Union flag which is still used by the United Kingdom.
The Union flag combines the flags of the St George's Cross, St Andrew's Saltire and St Patrick's Saltire.
Doesn't Ireland have another patron saint?
Yes, Ireland is lucky enough to have three patron saints. In addition to St Patrick, St Bridget and St Columba are patron saints of Ireland. St Bridget's feast day is celebrated on February 1, and St Columba is remembered on June 9, but March 17 is all about St Patrick.
Four myths about St Patrick
Many myths have been told about the figure of St Patrick. In order to determine the truth, we need to see what history can tell us about his life.
- St Patrick single-handedly converted the Irish people to Christianity. The truth: Historians believe that there were already Christian believers in Ireland by the time Patrick arrived. Ireland also had strong trading links with the Roman empire, and the religion is likely to have been spread.
- St Patrick defeated the pagan druids. The truth: This story is now believed to have been invented by a cleric, Muirchú, who lived two centuries later.
- St Patrick droves the snakes from Ireland. The truth: Well, there are no snakes in Ireland now (apart from those kept in zoos and as pets), but this may be because there never were any. Another theory is that the last Ice Age was too cold for snakes to survive and then the Irish Sea stopped them from breeding in Ireland.
- St Patrick explained the Holy Trinity using the shamrock. The truth: According to St Patrick's Day lore, Patrick used the three leaves of a shamrock to explain the Christian holy trinity: the Father, the Son, and the Holy Spirit. However, it is thought that this story was invented centuries later, according to experts.
When is the St Patrick's Day Parade?
St Patrick's Day parades are held in many cities around the world, drawing thousands of people. Last year was particularly poignant as Ireland marked the centenary of the 1916 Easter Rising, a key event in the country’s history.
This year's London St Patrick's Day Parade will take place on March 19. The The procession will makes its way down Piccadilly from 12pm, on a 1.5-mile route, passing some of London’s most iconic landmarks, including The Ritz, Piccadilly Circus, Trafalgar Square and onto Whitehall.
It is followed by a St Patrick's Day Festival in Trafalgar Square where revellers can watch St Patrick’s Day performances by West End stars, Irish acts and community choirs, plus a huge céilí on the stage, hosted by Irish stand-up comedian Jarlath Regan.
Festival-goers can then tuck into traditional and modern Irish food from the market, and enjoy special family activities for free. Find out more about the Trafalgar Square St Patrick's Day Festival.
Is St Patrick's Day a public holiday?
March 17 is a national holiday in Ireland, and in Northern Ireland. Although St Patrick is also the patron saint of Nigeria, the African country does not celebrate it as a national holiday.
St Patrick's day is a national holiday on the island of Montserrat in the Caribbean.
The island is also known as "the Emerald Isle" in memory of the Irish who settled there in the 17th century after Protestants expelled them from the neighbouring island of St Kitts.
An official green shamrock is stamped in your passport at the airport, and the national flag shows an Irish harp symbol. St Patrick's Day is also a provincial holiday in the Canadian province of Newfoundland.
Large numbers of Irish people emigrated to Newfoundland during the 18th and 19th centuries. Most were involved in the fishery trade.
How is St Patrick's Day celebrated?
Even those who aren't Irish and can't claim any ancestry turn out to celebrate St Patrick.
Some people choose to dress up in the colours of the Irish flag green, white and orange, or as a leprechaun, while others simply enjoy a traditional Irish stew or a pint of the black stuff.
It is worth noting that blue, not green, is the colour originally associated with St Patrick. “St Patrick’s Blue” is used on Ireland's Presidential Standard or flag (left), while the Irish Guards sport a plume of St Patrick’s blue in their bearskins.
The emphasis on green is thought to be linked to “wearing the Green”, a symbol from the 18th century on, of sympathy with Irish independence.
Until the 1970s, all pubs were shut in Ireland on St Patrick’s Day, the sole venue selling drink being the annual dog show. Lenten fasting – and the obligation to abstain from meat – were lifted on the day, which most families would begin with Mass.
More than 10 million glasses of Guinness stout are enjoyed every single day around the world, and 1,883,200,000 pints are sold every year – that's 1.8 billion. But on St Patrick's Day, that number is much higher.
Despite its ostensibly Irish origins, only one of Guinness’ five breweries is situated in Dublin, with the others located in Malaysia, Ghana, Cameroon and Nigeria, which is the largest Guinness stout market in the world by net sales value, according to its website.
Nigeria accounts for around a fifth of Guinness’ global sales, Euromonitor International data show, and is the stout’s second largest market, behind the UK and ahead of the US and Ireland.
Popular Irish toasts on St Patrick's Day, include: may the roof above us never fall in, and may we friends beneath it never fall out.
And there's even a Google Doodle
Google has dedicated its latest doodle to the mystical Skellig Michael, a remote island just off the coast of County Kerry, Ireland.
The breathtaking spot is a World Heritage Site and home to many species of seabirds, including puffins, gannets, and razorbills, that perch atop the island’s summit.
If you’re brave enough to scale the 600 steps to the top of the rocky precipice, you’ll see a magnificent view of the mainland and the Atlantic Ocean from 714 feet above sea level.
Scenes from Star Wars: The Force Awakens were shot on Skellig Michael at various points in 2015. (The word is that Luke Skywalker took up residency on the island.)
Want to know how to get there? Click here.
Why do people wear green on St Patrick's Day?
Wearing green has now become associated with St Patrick's Day, even though the saint was originally associated with the colour blue. It is thought that the shift happened for several reasons – Ireland's nickname is the 'Emerald Isle', there is green in the Irish flag and the shamrock, Ireland's national symbol, is also green.
According to Irish tradition, green is the colour of the Catholics and orange is the colour of the Protestants. On the Irish flag, these colours are separated by white, which is symbolic of peace between the two.
Green ribbons and shamrocks are said to have been worn as early as the 17th century.
According to legend, people wear green to makes themselves invisible to leprechauns, who would pinch anyone they could see (i.e. anyone not wearing green).
Some other St Patrick's Day celebrations
The White House celebrates St. Patrick's Day each year, dating back to the 1950s and has become an important standing engagement for Ireland, which has strong emotional and ancestral ties to the United States.
Donald Trump and Irish Prime Minister Enda Kenny participated in the annual shamrock ceremony on Thursday, a decades-old tradition in which Mr Trump was presented with a bowl of Ireland's famous greens.
In Chicago, thousands of people turn out to see the river being turned green, as part of a tradition that dates back to 1962.
The colouring process takes five hours and involves a mix of forty pounds of powdered green vegetable dye being tipped overboard a boat.
Other countries show their support by turning buildings green for the day, including the London Eye and HMS Belfast in London, Trinity College in Dublin, the Pyramids and the Sphinx in Egypt, Sydney Opera House in Australia, Burj Al Arab in Dubai and the Christ the Redeemer statue in Rio de Janeiro.
Some of the Emerald Isle's most breathtaking sights
The best Irish recipes
Why not whip up an Irish stew or traditional bread for St Patrick's Day? Here are some the best Irish recipes to make on March 17.
The best Irish drinks
Aside from Guinness, Ireland is also famous for its whiskey, poitin, stout, gin and Irish cream liqueur.
Here's a mixed bag to slake your thirst on March 17th.
Or try this recipe for a 'Shamrock Shake'.