Saint Piran is generally regarded as the patron saint of Cornwall (although Saint Michael also has some claim to this title). St Piran's flag is a white cross on a black background; St Piran's Day is March 5th.

He is the most famous of all the Irish saints who came to Cornwall. He is said to have discovered tin and is reputed to have founded the monastery of Clonmacnois (Clumaineteno).

It is said that at his death the remains of the Blessed Martin the Abbot which he had brought from Ireland were buried with him at Perranzabulo; his own remains were subsequently exhumed and redistributed to be used as reliquaries. Exeter Cathedral was reputed to be the possessor of one of his arms, while according to an inventory of St Piran's Church, Perranzabulo, had a reliquary containing his head and also a hearse in which his body was placed for processionals.

Legend: The heathen Irish tied him to a mill-stone, rolled it over the edge of a cliff into a stormy sea, which immediately became calm, and the saint floated safely over the water to land upon the sandy beach of Perranzabulo in Cornwall.