St Patrick's mission to spread Christianity to Ireland began and ended in Downpatrick. Ireland's patron saint is believed to have made his first convert at nearby Saul, and been buried at Down Cathedral; St Patrick's Day (17 March) sees the town filled with pilgrims and revellers.
Downpatrick – now County Down's administrative centre – was settled long before the saint's arrival. His first church here was constructed inside the earthwork dún (fort) of Rath Celtchair, still visible to the southwest of the cathedral. The place later became known as Dún Pádraig (Patrick's Fort), anglicised to Downpatrick in the 17th century.