the castle served as a military prison. During the 19th century, the castle was used as a barracks. In 1871, during the Paris Commune, insurgents were imprisoned there. In 1960, a house was built within the castle grounds by the governor of the island and the castle. Today, the keep houses the Noirmoutier Museum. The keep at the centre of the castle is solid and rectangular. Built of rubble, it has three floors with the lords' residence at the top. The keep has numerous murder holes and defensive turrets at the corners. The rectangular fortification consists of two towers, a single gate and two watch turrets in the four corners. At the beginning of the 18th century, the towers were reconstructed and the keep adapted for artillery. The Parish Church of Noirmoutier is dedicated to St. Philbert, who founded a monastery here around 674. where the monks' s had taken refuge after the invasion of Normandy in 875. A shrine at the altar contains relics of the saint and was classified as a historical monument in 1898. The church was first destroyed by the Saracens in 725 and 732. When the son of Charlemagne, Louis the Pious became King of Aquitaine, he inherited the rights to the church and in 801 ordered the reconstruction of the abbey and chapel. Forty five years later it was again destroyed by the Normans in 846. It was then rebuilt at the end of 11th century but rather more primitively than previously. Centuries later, the aisles were raised and it was consecrated in 1849. The neo-Romanesque bell tower was built in 1875 to replace the old bell tower which was destroyed by fire in 1848. On the inside is a model frigate, made by an artisan watchmaker of the village in 1802 for Augustus Jacobsen. The church received the body of St. Philbert some time between 690 and 836, when he was transferred to Saint-Philbert-de-Grand-Lieu, where the monks had taken refuge after the invasion of Normandy in 875. A shrine at the altar contains relics of the saint and was classified as a historical monument in 1898. Jacobsen Dam was built in 1812 by John Cornelius Jacobsen, descendant of a family of Dutch who came to the area in the eighteenth century . This dam has allowed the development of salt marsh s, creating a towpath and a channel to access the port. Along