St. Patrick was born in Roman Britain, around 389. When he was 16, he was sold into slavery to Ireland where he was a shepherd for 6 years. While in captivity he studied and turned to religion. He escaped slavery and later returned to Ireland as a missionary, determined to convert Ireland to Christianity. He used the shamrock to explain the Holy Trinity. He was ordained as Bishop of Ireland in 431. He was able to secure tolerance for Christians in Ireland during his life there. He is said to have died in 461 and to be buried in Downpatrick. St. Patrick's Cathedral in Dublin was built in the 12th Century. He is also said to have drummed the snakes from Ireland and into the sea.