In 1424, in the early 15th century, when there was but an obscure village, Evrard d’Arenberg, Count of Marck, began building a very powerful castle on a rocky outcrop around the remains of the church of St. Martin. This castle, consisting of a large number of towers and buildings built over several centuries, was part of the Principality of Sedan where several La Marck princes succeeded each other over half a century. The castle of Sedan, the largest medieval castle in Europe (35,000 m²), fully classified as a French Historical Monument, was returned to the city in 1962 and welcomes 80,000 visitors each year. It has housed a museum and a unique hotel facility since August 2004.