We celebrate Saint Patrick's Day each year on March 17th.
He was born somewhere near the end of the 4 century and took on the name Patrick. Maewyn Succat was kidnapped from his native land of Britain, by a band pirates. After 6 long years of slavery he scarped to the northern coast of Gaul.
In Gaul, Maewyn became Patrick and studied in the monastery under St. Germanic bishop of Auxerre. He came to believe that it was his calling to convert the pagans of Ireland to Christianity. He used the shamrock, which resembles a three-leafed clover, to help explain the concept of the Trinity.
Patrick was arrested several times, but escaped each time. Legend has it that St. Patrick drove all the snakes out of Ireland. Evidently, they all went into the sea and drowned. The snake is a pagan symbol.
Patrick's mission in Ireland lasted for thirty years. He then retired to County Down and died on March 17 in 461AD. That day has been commemorated as St. Patrick's Day ever since.