Patron of Watchet and St Decumans (Somerset), was probably a 6th-century Welsh monk who came from Rhoscrowther (= Llandegyman) in Pembrokeshire (Dyfed) and settled in North Somerset, near Dunster. The 15th-century Life in N.L.A. says that he lived as a hermit there and met an entirely unprovoked death by decapitation at the hand of an assassin while he was at prayer. After this, the body carried the head to a nearby well (like Nectan and others). His cult was firmly established at Wells and Muchelney; dedications to him in Cornwall, Wales, and Somerset are more probably due to disciples than to his own itinerary. The usual day for his feast is 27 August, but Norwich (and Roscarrock) kept his day on 30 August.
From The Oxford Dictionary of Saints in Oxford Reference.