St. Patrick of Ireland is one of the world's most popular saints. He was born in Roman Britain and when he was fourteen or so, he was captured by Irish pirates during a raiding party and taken to Ireland as a slave to herd and tend sheep.
At the time, Ireland was a land of Druids and pagans but Patrick turned to God and wrote his memoir, The Confession. In The Confession, he wrote: "The love of God and his fear grew in me more and more, as did the faith, and my soul was rosed, so that, in a single day, I have said as many as a hundred prayers and in the night, nearly the same.
I prayed in the woods and on the mountain, even before dawn. I felt no hurt from the snow or ice or rain." Patrick's captivity lasted until he was twenty when he escaped after having a dream from God in which he was told to leave Ireland by going to the coast. There he found some sailors who took him back to Britain and was reunited with his family.
Patrick preached and converted all of Ireland for 40 years. He worked many miracles and wrote of his love for God in Confessions. After years of living in poverty, traveling and enduring much suffering he died March 17, 461.
He often used shamrocks to explain the Holy Trinity and entire kingdoms were eventually converted to Christianity after hearing Patrick's message.