Different tales tell of his standing upon a hill, using a wooden staff to drive the serpents into the sea, banishing them forever from the shores of Ireland. One legend says that one old serpent resisted, but the saint overcame it by cunning. He is said to have made a box and invited the reptile to enter. The snake insisted the box was too small and the discussion became very heated. Finally the snake entered the box to prove he was right, whereupon St Patrick slammed the lid and cast the box into the sea. While it is true there are no snakes in Ireland, chances are that there never have been since the time the island was separated from the rest of the continent at the end of the ice age. As in many old pagan religions serpent symbols were common, and possibly even worshipped. Driving the snakes from Ireland was probably symbolic of putting an end to that pagan practice. Patrick is most known the world over for having driven the snakes from Ireland.

It is known that he was born Maewyn Succat in 387 Kirkpatrick Scotland or Britain depends and his father was Calpurniuson your source and was kidnapped by Irish raiders and sold in Ireland as a slave for Milcha in Dalaradia for around 6 years. He eventually fled from his cruel master and during a  vision in a dream he was led to God and he fled to Britain in ship.

 He became fluent in the Irish language before making his escape to the continent, to Gaul where for 12 years he studied under St Germaine the Bishop of Auxerre, at St Martin's monastery.  Eventually he was ordained as a deacon, then priest and finally as a bishop. Pope Celestine in Rome then sent him back to Ireland in the name Patercuis or Patritus to preach the gospel and convert the pagans to be Christians. 

Patrick was very successful in his conversions upsetting the Celtic locals. Evidently he was a great traveller, especially in Celtic countries, as innumerable places in Brittany, Cornwall, Wales, Scotland and Ireland are named after him. He establish many monasteries, churches and Educational facilities. He spent around 30 years in Ireland. He died March 17 in AD 460, AD 461, or AD 493 once again depends on your source and his grave is in St Bridget and St. Columbia, at Downpatrick, County Down. The jawbone of St. Patrick was preserved in a silver shrine and was often requested in times of childbirth, epileptic fits and as a preservative against the evil eye. Another legend says St. Patrick ended his days at Glastonbury and was buried there. The Chapel of St. Patrick still exists as part of Galstonbury Abbey. There is evidence of an Irish pilgrimage to his tomb during the reign of the Saxon King Ine in A.D. 688, when a group of pilgrims headed by St. Indractus were murdered.

 The Shamrock

At one time called the "Seamroy", symbolises the cross and blessed trinity. Before the Christian era it was a sacred plant of the Druids of Ireland because its leaves formed a triad. In the most simplest form he explained the Holy Trinity with the Shamrock. The well-known legend of the Shamrock connects it definitely to St. Patrick and his teaching. Preaching in the open air on the doctrine of the trinity, he is said to have illustrated the existence of the Three in One by plucking a shamrock from the grass growing at his feet and showing it to his congregation. The legend of the shamrock is also connected with that of the banishment of the serpent tribe from Ireland by a tradition that snakes are never seen on trefoil and that it is a remedy against the stings of snakes and scorpions. The trefoil in Arabia is called shamrakh and was sacred in Iran as an emblem of the Persian triads. The trefoil, as noted above, being a sacred plant among the Druids, and three being a mystical number in the Celtic religion as well as all others, it is probable that St. Patrick must have been aware of the significance of his illustration. For one final word from us about St. Patrick's Day and links to a few Irish sites of interest...

Some nice links