Complex sentence: It was founded in 1947 by Philippe and Hélène Viannay, who had been involved with the French Resistance during World War II. Its first site was the Glénan archipelago, about off the coast of southern Brittany.
Split into simpler sentences: It was founded in 1947 by Philippe and Hélène Viannay, who had been involved with the French Resistance during World War II. It's first site was the Glénan archipelago, about off the coast of southern Brittany.