And for more than 50 years the citizens of Chicago have turned their river green with huge vats of vegetable dye to commemorate St Patrick on March 17 every year.

The general air of revelry might just come as something of a surprise to the fifth century missionary who dedicated his life to preaching Christianity in Ireland. And just how much do most of us know about Paddy when we raise a glass or 10 of Guinness in his name? Here’s your zappy TNT guide to the great man.

Patrick was born to a family of Christian clergy in around 385 on the west coast of Britain, somewhere between the Clyde and the Severn estuary. Yes, folks, there’s good reason to suppose that good old Paddy was actually a Welshman.

He suffered a slight shock to the system when he was kidnapped by pirates at the age of 16. He was enslaved in Ireland, where he worked as a shepherd – possibly in Antrim. He escaped six years later and returned to England, but was beset by visions telling him to return to Ireland and spread the Christian message.

He did just that, but the popular belief that he single-handedly brought Christianity to the Emerald Isle is probably wide of the mark – the religion had almost certainly filtered to Ireland via Roman Britain before Patrick’s time.

Other popular stories surrounding Patrick’s life are also unlikely to be true. For example, there is no real reason to suppose that he defeated the pagan druids, or that he used the three-leaved shamrock to illustrate the Christian doctrine of the Holy Trinity. The shamrock story was probably invented in the 18th century.

Patrick is also said to have banished snakes from Ireland by driving them into the sea at the end of a 40-day fast in which he was tormented by serpents. It is perfectly true that there are no snakes in Ireland to this day. However, the reality is that it was too cold for them to survive there during the last ice age.

Myths they may be, but the snake and the shamrock remain the emblems of St Patrick, who was aged around 76 when he died some 1554 years ago today on March 17, 461. Cheers!