He went from Wales to seek his ideal location for the simple life. This turned out to be Hartland Point in Devon.
The serenity turned sour when a couple of thieves ran off with his two cows. He chased after them and attempted to convert them (the thieves, that is, not the cows). The two miscreants just laughed and sliced his head off.
We imagine they stopped laughing when our hero calmly picked his head up and carried it back to his homestead, leaving a trail of blood drops. He then dropped his head into his well and presumably expired.
Wherever his blood fell, foxgloves appeared. So on his feast day a procession of children carry foxgloves to the well. We don’t know what happened to the cows.