Gradually, secular housing spread across the full surface of the castellumCastellum sancti Dionysii ------------------------------------------------------ fortification built by Charles the Bald in 869 around the abbey of Saint-Denis; the zone delimited by the walls of this castellum.. Despite widespread excavation, it is difficult to get an accurate idea of how the monastic town was organized. The concentric layout of the streets, which converge towards the monumental core, structured the growing town and became fixed from the year 1000. On the other hand, the layout of secondary streets remained in flux until the thirteenth century, since housing plots had not yet stabilised. The structures uncovered during excavations correspond to houses made of wood. Stone was only used for building collective wells. The floor plans of the houses are too fragmentary for us to attempt a reconstruction. The town's housing was accompanied by various annexes. These include weaving workshops-built partly below ground level-in which the marks left by the looms are still visible, and a tanning pit. which indicates that furrier prepared animal hides. The presence of a number of grain-storage pits, show that the population maintained some agricultural activities.