Saint Patrick's Day is observed on 17 March, the supposed date of his death. It is celebrated inside and outside Ireland as a religious and cultural holiday.
1. St. Patrick is the patron saint of Ireland, although he was born in Britain, around 385AD. His parents Calpurnius and Conchessa were Roman citizens living in either Scotland or Wales, according to different versions of his story.
2. As a boy of 14 he was captured and taken to Ireland where he spent six years in slavery herding sheep. He returned to Ireland in his 30s as a missionary among the Celtic pagans.
3. Legend has it that he used the native shamrock as a symbol of the holy trinity when preaching and brought the Latin alphabet to Ireland.
4. Miracles attributed to him include the driving of serpents out of Ireland. However, evidence suggests post-glacial Ireland never had any snakes in the first place.
5. Wearing green, eating green food and even drinking green beer, is said to commemorate St Patrick's use of the shamrock - although blue was the original colour of his vestments.
6. St Patrick was said to have proclaimed that everyone should have a drop of the "hard stuff" on his feast day after chastising an innkeeper who served a short measure of whiskey. In the custom known as "drowning the shamrock", the shamrock that has been worn on a lapel or hat is put in the last drink of the evening.
7. 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.
8. St. Patrick's Day was first celebrated in America in Boston, Massachusetts, in 1737. Around 34 million modern Americans claim Irish ancestry.
9. It is believed that St Patrick died on March 17 in 461AD. It is a national holiday in Ireland, and on the island of Montserrat in the Caribbean, which was founded by Irish refugees. It is a bank holiday in Northern Ireland and a provincial holiday in the Canadian province of Newfoundland.
10. Dublin has a parade that attracts hundreds of thousands of people, while in Chicago the river is dyed green for a few hours. The biggest parade is normally held in New York, while the largest celebration in the southern hemisphere is in Sydney, Australia.