The history of the commune dates back to before the era of the Roman invasion when it was a small settlement inhabited by Gauls. The Roman invasion encouraged the small hamlet to grow into a small village and after the Romans left France the village soon came under the power of the Franks.
In 611, the Gualaric monk known as Valery arrived in the area. He installed himself as a hermit on the headland of the site of Leuconaus. His virtue and miracles quickly attracted disciples. These disciples formed a primitive abbey. The saint was then buried there in 622 and became known as Saint Blimont. Clotaire II (King of Neustrie) provided the foundations of the new abbey in 627. The relics of the saint attracted many pilgrims to the abbey which had become known as Saint-Valery. During the 8th and 9th century, the abbey and village were plundered and devastated on several occasions by the Vikings.
The village grew during the 10th and 11th centuries and was historically significant as the site where William the Conqueror assembled his fleet before sailing over to England in 1066. During the many wars between the French and the English the village passed between French, English and Burgundian ownership. The English destroyed the abbey and cloister in order to strengthen the nearby St Valery castle. In 1431, Joan of Arc, captive of the English, was held prisoner in the local prison where she was then conveyed to Rouen and burnt at the stake. The cell in which she stayed can still be found near part of the old village walls.
