Erin go bragh! St Patrick's Day, the annual celebration of the patron saint of Ireland, is here.

Every year, the people of Ireland celebrate their heritage and culture on St Patrick's Day, with the day growing as a commercial occasion rather than a religious event in recent times.

While Ireland embraces its patron saint's day by holding vibrant, green parades, wearing shamrocks and flying Irish flags more than usual, celebrations also take place in other countries around the world, including the UK and United States. However, many of this year's events have been cancelled or postponed due to the coronavirus outbreak.

Here is everything you need to know about St Patrick's Day, from the patron saint himself to Irish recipes and worldwide celebrations.

When is St Patrick's Day 2020?

St Patrick's Day falls on March 17 each year. The Irish have celebrated St Patrick for more than 1,000 years, and Waterford Franciscan Luke Wadding, helped put the feast day on the Catholic Church calendar in the early 1600s.

The first public celebration of St Patrick's Day is debated. While many argue that the first parade in the name of the saint was held in Boston, Massachussetts, in 1737, with New York holding the first "official" parade in 1762, historian Dr Michael Francis has since pinpointed that the very first celebration was in St Augustine, Florida, in 1600.

Since these early events, the celebration of St Patrick has spread to Dublin and many US cities, and in recent years has grown in popularity elsewhere, including Europe and Asia.

Who was St Patrick?

St Patrick's exact birthplace is unknown and debated. Born Maewyn Succat around the year of 385 AD in either England, Scotland or Wales, the patron saint was captured by Irish pirates at the age of 16 and taken to Ireland as a slave.

Working as a shepherd, Patrick was held captive for six years and grew closer to spirituality and prayer during this period of isolation. After a "voice" told him it was time to leave Ireland, Patrick successfully fled his master and sailed back to Britain to continue studying Christianity.

Shortly afterwards, an angel appeared to Patrick in a dream and told him to go back to Ireland as a missionary. But first he decided to travel to Gaul, to study religious instruction under Germanus, bishop of Auxerre.

He returned to Ireland as the country's second bishop and began his mission to spread the Christian message to those who had never heard it. He converted thousands of people to Christianity and established councils, churches, schools and monasteries across the country.

Legend suggests that Patrick used the three-leaf shamrock on his mission to explain the Holy Trinity, teaching his followers that the Father, the Son and the Holy Spirit exist as individual elements of the combined entity. While some experts claim this story was invented centuries later, the tale has led to the common practice of people wearing the symbol on the feast day.

Patrick is also believed to have banished snakes from Ireland to help remove the evil and introduce a new age. But experts say this is a myth because of evidence that snakes never existed in the country in the first place.

Around 431 AD, Patrick was appointed as successor to St Palladius, the first bishop of Ireland, and during his later years, he wrote about his spirituality and life in his "Confession".

Believed to have died on March 17, in 461 AD, Patrick's spiritual path led him to become a legendary figure, as he left behind an established church and an island of Christians. Today, his work is commemorated annually on March 17.

Symbols and images associated with Ireland and St Patrick's Day

The national flag of Ireland, also known as the Irish tricolour, is a prominent symbol in St Patrick's Day parades, events and celebrations. The green stripe stands for Irish Catholics, while the orange stripe represents Irish Protestants. The central white stripe also represents the hope for peace between the two groups.

The patron saint of Ireland is traditionally linked to the red Saltire of St Patrick, which was used to form the the flag of the United Kingdom.

St Patrick is also associated with the colour blue, after the creation of the Order of St Patrick in the 1780s made it the official colour. "St Patrick’s Blue" can be found on Ireland's Presidential Standard, and in the plume of bearskins worn by the Irish Guards.

The legend of the leprechaun has also become a modern-day symbol of Ireland. Known for their mischievous behaviour and for leaving pots of gold at the end of rainbows, today, the mythical creatures feature heavily as a tourist symbol and some people choose to wear leprechaun costumes and hats to St Patrick's Day parades. Dublin even has its very own Leprechaun Museum.