See also Château Grimaldi (disambiguation) for other Châteaux of the same name The Château Grimaldi at Cagnes-sur-Mer in the département of Alpes-Maritimes, in France, is built on the site of an earlier fortress occupied by the Greeks and then the Romans. The present castle was built in 1309 by Rainier Grimaldi (Lord of Cagnes and an admiral of France) - a distant ancestor of the present ruling house of Monaco. Later it became the residence of the Governors of the province. Following the French Revolution, it was used as barracks and later as a hospital. Now owned by the city of Cagnes, it is known as le Château Musée Grimaldi (the Grimaldi Castle and Museum).