According to legend, Paul Aurélien in the 6th century relieved Batz Island of a dragon who was terrorising the island.

Together with a young warrior who was living near Cléder, Paul Aurélien went to the lair of the monster and ordered it to go outside.

The Saint put his stole around its neck and took it to the west point of the island where he ordered it to hurl itself over. From that time, this place is called the “toul ar sarpent” in Breton.