Some doubtless are of extreme antiquity, but the majority are comparatively modern. It is a significant fact that the entrance to perhaps the majority is in the sacristy of the parish church, and in that at Gapennes care was taken not to undermine the tower of the church. M. de Carpentin, who explored and reported on the excavation at Gapennes, remarks on the care taken to so distribute the chalk brought up from these passages and vaults that no heaps were anywhere visible. "The motive that can have induced the undertaking of such an extensive work can only have been that necessity drove the inhabitants to create for themselves a refuge in time of war." In it he found two pieces of common pottery, a lock and a hinge of iron, some straw and leather soles of women's shoes. He adds: "At the entrance of several of the chambers the stone is worked to receive doors, and here portions of decayed wood were found. And many of the chambers had their walls blackened by smoke as of lamps." At Naours in Somme, the underground galleries have been explored thoroughly; there are several circular chambers for stores, and corn has been found in them, also fourteen gold coins of Charles VI or Louis XIV. In all there are 201 galleries and 300 chambers and the labyrinth extends to the distance of 6000 feet. At Santerre, which possesses three of these refuges, that portion of its territory was called _Territorium Sanctæ Libertatis_. The north-east of France, Picardy and Artois, were always exposed to attack from pirates by sea, Northmen and Saxon, and from invaders over the border. But none of these can have exceeded in barbarity that of 1635 to 1641, when Spanish armies--the first under John de Werth and Piccolomini, 40,000 in number, and made up of Germans, Hungarians, Croats as well as Spaniards--poured over the provinces committing the most frightful atrocities. And precisely to this period some of the refuges may be referred.