Copper work has existed since the Middle Ages: stove-making, brassware, boiler-making. Norman workshops continue to perpetuate the French tradition and expertise. Numerous golden ornaments were placed on the roofs of the abbey and on its spire. Made of copper – a lighter metal than bronze which is better suited to slender structures – they were gilded by hand according to the rules of the art by the workers of Gallis, a Seine-Maritime company specialising in the restoration of historical monuments.