In later life, he served as a bishop, but little is known about the places where he worked.
In the dioceses of Ireland, it is both a solemnity and a holy day of obligation; it is also a celebration of Ireland itself.
The Declaration is the more biographical of the two.
In it, Patrick gives a short account of his life and his mission.
Ireland, Nigeria, Montserrat, Archdiocese of New York, Roman Catholic Archdiocese of Newark, Boston, Rolla, Missouri, Loíza, Puerto Rico, Murcia (Spain), Clann Giolla Phádraig, engineers, paralegals, Archdiocese of Melbourne; invoked against snakes, sins) was a fifth-century Romano-British Christian missionary and bishop in Ireland.
Known as the "Apostle of Ireland", he is the primary patron saint of Ireland, along with saints Brigit of Kildare and Columba.
He is also venerated in the Anglican Communion, the Old Catholic Church and in the Eastern Orthodox Church as equal-to-apostles and the Enlightener of Ireland.
The dates of Patrick's life cannot be fixed with certainty but there is broad agreement that he was active as a missionary in Ireland during the second half of the fifth century.
Early medieval tradition credits him with being the first bishop of Armagh and Primate of Ireland, and they regard him as the founder of Christianity in Ireland, converting a society practising a form of Celtic polytheism.
He has been generally so regarded ever since, despite evidence of some earlier Christian presence in Ireland.
According to the Confessio of Patrick, when he was about 16, he was captured by Irish pirates from his home in Great Britain, and taken as a slave to Ireland, looking after animals, where he lived for six years before escaping and returning to his family.
After becoming a cleric, he returned to northern and western Ireland.