uvre Museum, French Musée du Louvre, official name Great Louvre, French Grand Louvre, national museum and art gallery of France, housed in part of a large palace in Paris that was built on the right-bank site of the 12th-century fortress of Philip Augustus. In 1546 Francis I, who was a great art collector, had this old castle razed and began to build on its site another royal residence, the Louvre, which was added to by almost every subsequent French monarch. Under Francis I, only a small portion of the present Louvre was completed, under the architect Pierre Lescot