St Patrick

Saint Patrick's name at birth was Maewyn Succat and he was born in Wales around AD385. Until the age of 16, Maewyn considered himself a pagan, but he was sold into slavery by a group of Irish marauders that raided his village and during his captivity, he converted to Christianity. He escaped from slavery after six years and went to Gaul where he studied in the monastery under St Germain, bishop of Auxerre for twelve years. . During his training for the priesthood, Maewyn changed his name to Patricus or Patrick and became aware that his calling was to convert the pagans of Ireland to Christianity.
After two years, Patrick was appointed as second bishop to Ireland. He was quite sucessful at winning converts, and this upset the Celtic Druids. Patrick was arrested several times, but managed to escape. He travelled throughout Ireland establishing monasteries and setting up schools and churches to aid in converting the Irish to Christianity.
Legend has it that Saint Patrick drove all the snakes out of Ireland. Evidently they all went into the sea and drowned. The snake is a pagan symbol and perhaps this is a figurative tale explaining that he drove paganism out of Ireland.
His mission in Ireland lasted for 30 years. Afterwards, Patrick retired to County Down and he died on March 17th AD461. This date has been commemorated as St Patrick's Day ever since.

The Shamrock and The Four Leaf Clover

There is no such thing as a 'Shamrock Plant'. The word Shamrock comes from the Irish word 'seamrog' meaning 'little clover'. White Clover in particular was held in great esteem by the early Celts of Ireland as a charm against evil spirits. This pagan tradition was continued by early Christian leaders and Patrick used the three leaf shamrock to explain the Trinity. He used it in his sermons to represent how the Father, the Son, and the Holy Spirit could all exist as seperate elements of the same entity. It then became the custom to wear shamrock on his feast day.
The four leaf clover is a universally accepted symbol of good luck with it's origin going back thousands of years. The Druids considered four leaf clovers to be especially significant and a portent of good luck. It is said that the first leaf is for hope, the second for faith, the third for love, and the fourth for luck.

Leprechauns

The leprechaun is an Irish fairy. The name leprechaun is derived from the old Irish word 'luchorpan' which means 'little body', and leprechauns are still known as 'the little people.
A leprechaun looks like a small old man (about 2 feet tall), dressed in green, sometimes with a leather apron, wearing buckled shoes and three-sided hats, a symbol of the ancient Irish Triple Goddess. According to legend, leprechauns are aloof and unfriendly, live alone, and pass the time making shoes.
Leprechauns are best known for their pots of gold. It is said that you can track down a leprechaun by the sound of his shoemaker's hammer. If caught, he can be forced to reveal the whereabouts of his treasure. But do not take your eyes off him for a second! The moment you do, he will immediatly vanish and all hopes of finding the treasure are lost.

The Blarney Stone is a stone set in the wall of the Blarney Castle tower in the Irish village of Blarney, County Cork. The stone is believed to be half of the Stone of Scone which originally belonged to Scotland. Scottish Kings were crowned over the stone because it was believed to have special powers. The stone was given to Cormac McCarthy by Rober the Bruce in 1314 in return for his support in the Battle of Bannockburn. Queen Elizabeth 1 wanted Irish chiefs to agree to occupy their own lands under title from her. Cormac Teige McCarthy, the Lord of Blarney, handled every Royal request with subtle diplomacy, promising loyalty to the Queen without 'giving in'. Elizabeth proclaimed that McCarthy was giving her "a lot of Blarney". The legend was born.
Kissing the stone is supposed to bring the kisser the gift of persuasive eloquence (blarney). The legend says that an old woman cast a spell on the stone to reward a King who had saved her from drowning. Kissing the stone while under the spell gave the King the ability to speak sweetly and convincingly. It's hard to reach the stone, it's situated between the main castle wall and the parapet. Kissers have to lie on their back and bend backwards (and downwards) holding iron bars for support.