In 385 A.D., St. Patrick was born near Dumbarton, Scotland to Roman-British parents, so he was Roman-British by birth. At the age of 14, he was captured and enslaved by Irish raiders, who put him to work tending sheep in Ireland.
At the age of 20, St. Patrick escaped from his captors and returned to his family. He trained in France to become a priest with the guiding thought that one day he'd return to Ireland and convert the pagan land to Christianity. On March 25, 433 A.D., he landed at Slane, Ireland, as an ordained bishop, and later converted the chieftain of one tribe, Dichu, by allegedly temporarily paralyzing his arm.
St. Patrick traveled throughout the island for decades with his disciples, converting thousands and building churches. He died at Saul, where he'd built his first Irish church, on March 17, 461 A.D.