In the 12th century, the village of Marennes was a priory of the Abbey of Saintes. In the 14th century, it was incorporated into the royal domain by Charles V, who removed it from the jurisdiction of Saintes to transfer it to that of La Rochelle. At the end of the 14th century, Charles VI gave it the title of county. A church existed from the 11th century, rebuilt between the 11th and the 15th century. During the Wars of Religion, tradition has it that the church served as a temple and a fortress. At the beginning of the 17th century, the building was ruined, except for its bell tower. The rebuilding was launched in 1602 and completed in 1770. The building is covered with a roof around which reigns a sort of rampart surrounded by a projecting parapet resting on a row of consoles which feature machicolations. The bell tower is of ogival style. Its plan is quadrangular at the base and buttresses surmounted by triangular pediments. It is surmounted by a freestone spire, octagonal, furnished with projecting hooks on the edges and a series of triangles placed on the openings. Four acute pinnacles make up, on each face, the axis of the base of this arrow.