The Life of Saint Patrick
Not much is known about his early life, about from what he wrote in two surviving letters and what is written in accounts of his contemporaries. Even his birthplace is disputed. Patrick himself says he was born in Banna Venta Berniae, but he doesn't identify the location of that place, and it is otherwise unknown. Another tradition says that Patrick was born in Scotland, at Kilpatrick, in 387 A.D., to parents named Calphurnius, a Roman officer, and Conchessa.
When he was 16, Patrick was captured by a band of Irish ruffians and sold into slavery to Milchu, a chieftain in Dalriada, in present-day County Antrim, Ireland. Milchu was also a druidical high priest, who taught Patrick the Celtic language and the nature of the druids' faith. Patrick was still a slave, though, and was treated cruelly. After six years, he escaped, making his way to Britain and then to France.
Patrick joined the company of some famous religious men of the time, among them Germain, the Bishop of Auxerre. Patrick embraced the Christian faith and was later named a priest.
He studied for 18 years, including a visit to Pope Celestine I in Rome. From that visit came Patrick's famous visit to Ireland, beginning in 433.
He is primarily known as the "Apostle of Ireland," for his role in convincing many people in Ireland to profess Christianity as their religion. In many cases, these people left the faith that they grew up with and embraced the new religion. His learnings from his chieftain master came in handy in his endeavors.
Patrick is said to have performed miracles and to walked many miles on his journey around Ireland. He is also said to have driven all the snakes from Ireland. Not much proof of his miracles or his snake-banishing exists.
One thing that is known for sure is that Patrick made use of the shamrock in his religious teachings, to illustrate the idea of the Christian Trinity ("Father, Son, and Holy Ghost/Spirit"). The three-leaf shamrock would have been familiar to native Irish people, who saw the shamrock in a similar way with regard to their three sacred goddesses.
This was one a few instances of Patrick's using familiar symbols to illustrate the appeal of Christianity. Another was the use of a bonfire on Easter, a practice with which Irish people would have also honored their gods. Another, more highly visible activity in this vein was Patrick's adding a sun to the Christian cross to create what is now the Celtic cross.
Patrick died on March 17, 461. The holiday that bears his name celebrates his life and accomplishments.