St. Patrick wasn't actually Irish. He was Welsh and was born with the name Succat. At 16 years old he was kidnapped by Irish raiders and brought back to the Emerald Isle and sold as a slave. His master made him herd sheep all by himself for 6 years before he had an epiphany from God. He told Succat that he would help him escape if he promised to go to Rome and accept Christ. Desperate for freedom, Succat agreed. He ended up having several lucky breaks and made his way to Rome where he studied and became a saint. The pope told him one day that he wanted to convert the "barbaric Irish" to the ways of Catholicism. Succat suggested that he be sent because he knew the language and how Irish people worked and thought. So, the pope agreed. St. Patrick first converted the kings because he knew if the kings were one religion, his followers would be that much easier to convince. After that, he roamed Ireland, converting those he came across. He noticed that the Irish were having trouble grasping the concept of the Holy Trinity during one of his lectures. He thought for a moment, then plucked a shamrock, which has three leaves. He used each leaf to represent each part of the Holy Trinity (father, son, holy ghost) and said the stem holds it together making it one piece and it worked. The Irish understood that. It has been the symbol of Ireland and St Patrick ever since.