An architectural monument of national importance, occupied since 1258 by over 20 generations of Ysenburgs. Erected in the 20th century in form of a moated castle to protect the extensive forests of the realm, it consisted of the tower, the keep, the and a Romanesque chapel surrounded by a massive 13-sided defence wall. Many Gothic and renaissance additions followed. Significant is the late Gothic chapel with carved choir stalls. Guided tours allow access to the historic interior. The outer castle court is enclosed by a circle of buildings which gave westerly protection.