In early Christian times Pol Aurelia arrived from Ushant to preach to the islanders. The island governor begged the saint to deliver them from a horrible monster which terrorized the population. Pol agreed to do so and, wearing his holy vestments, followed his guide, a gentleman from the canton of Cledar, to the mouth of the dragon's cave. There they were met by the angry serpent advancing towards them. Pol lasooed it round the neck with his stole and led it to the water's edge where he ordered it to return to the depths. This it meekly did at a place on the north which today bears the name.........The two heroes were well rewarded. Pol was given a palace which he converted into a monastery and his guide was given the honor that he and his descendants would from then on attend important religious festivals armed with a sword. Pol went on to perform further miracles when he blessed a spring the water of which cured three blind men, two mute men and a paralytic. He died in about the year 600 AD and was buried at Saint Pol-de-Leon.
The history still reveals that English incursions, at the XIV 2nd century, disturbed the life of the island. Iliennes pushed back one of them by directing their churns with butter in anfractuosities of the rocks. An old proverb islander claims: "Nor three, nor hundred English does not frighten me ". The revolution, in the island, did not pass without leaving of trace. Thus of 1793 to 1799, one carried out burials without priestVeil and water sports are practised at the same time in the Island of Batz and Roscoff, board with veil, kayak of sea, centre-board etc... 2 hiking roads make it possible to skirt the score of beaches and the 14 km of coastal paths.
The islanders also balked to lodge the soldiers who came to remove all to them. This hostility with the soldiers did not prevent the islanders from giving hunting to English frigates. In 1940, some islanders crossed the English Channel to join General de Gaulle in London.