Built in 1424 on the ruins of a Benedictine convent, the castle of Sedan is purest medieval style. At that time, it was the width of the walls that made a place strong. These range from 7 to 27 meters (22 to 88 ft) thick. This fortress was deemed to be impregnable as it was resistant to all bullets and other projectiles. It is the largest fortress of medieval origin in Europe with 35,000 m² (8,64 acres) over seven floors. Sedan was a principality of 21 villages. The villagers could take refuge there in the event of an attack. The castle of Sedan holds a record: it is the largest fortress in Europe. Living up to its motto: Undique Robur (in Latin: strength everywhere).