St. Patrick was born in either Scotland or Wales, the son of Roman parents living in Britain. When he was about fifteen or sixteen, he was captured and enslaved by an Irish chieftain during a raiding party across the sea. He spent several years enslaved in Ireland, herding and tending sheep and swine. It was during his captivity that St. Patrick dedicated his life to God. Legend has it that St. Patrick escaped captivity and Ireland after a dream in which God instructed him to journey to the Irish coast where he found a ship that returned him to his family.
After years of religious study, he became a priest. According to a document known as "The Confession," St. Patrick heard the voice of the Irish in his dreams, "crying to thee, come hither and walk with us once more." Eventually, Pope Clemens commissioned St. Patrick as bishop to preach the gospel to the Celtic people. Arriving back in Ireland, he commenced an incredible mission, travelling across the country, preaching and baptizing, ordaining priests and bishops, erecting churches and establishing places of learning and worship, despite constant threats to his life. It has been said that he and his disciples were responsible for converting almost all the population of Ireland to Christianity.
St. Patrick found that the pagan Irish had great difficulty comprehending the doctrine of the Trinity, so St. Patrick held up a shamrock (similar to a three-leaf clover) to show how the three leaves combined to make a single plant, just as the Father, Son, and Holy Ghost combined to make the holy Trinity. Since that time, the shamrock has been the symbol of the land.