In the Early Middle Ages, attempts were made to colonise the island that separated the western and southern channels of the Gironde Estuary. The name Cordouan had not yet been bestowed on it. Increasing trade with Bordeaux led successive authorities to occupy the island to signal its presence and to limit the tolls paid by sailors. When the English crown ruled the Duchy of Guyenne, a tower was built in the fourteenth century. Archival documents have helped dispel the mystery that surrounded the origin of Cordouan, and which contributed to the magic of the place.