Royaumont Abbey was returned to its original purpose in 1869, with the installation of the nuns of the Sainte-Famille de Bordeaux. Major restorations were then carried out, under the responsibility of the architect Louis Vernier. A neo-Gothic architecture was restored to all the monastic buildings. In the Middle Ages, the large monks’ building had two levels: the sacristy and the chapter house on the ground floor, and the monks’ dormitory upstairs. The industrialists destroyed the vaults and built three floors. Vernier preserved these levels and pierced the ground floor with a series of ribbed vault windows.