St Petroc was a Welsh Celtic saint who came to Cornwall and landed at Padstow. Here he established a Christian community before moving inland to Bodmin, on the instructions of an angel. He linked with St Guron and took over his prayer cell, whilst Guron travelled to the south coast and established prayer cells at Gorran Haven and Fowey. Petroc's holy well still exists in Priory Park Bodmin.
Petroc built a monastery in Bodmin which became well renowned in its time, training monks and releasing them to evangelise. He also travelled widely abroad including to Jerusalem and India, before returning to Cornwall where he died.