he Altenkamp house was first mentioned in 1394 as the castle seat of a branch of the lords of Düthe who lived there and acquired the Tunxdorf house. In 1601 the branch of the Lords of Dünthe-Altenkamp died out and the castle passed to the line of Düthe-Fresenburg. In 1687 this line also died out and its possessions went to the then son-in-law Johann Caspar von der Ruhr. His death in 1687 meant the end of the common history of the houses Altenkamp and Tunxdorf, because when the property was divided between the sons Johann Caspar and Gerhard Tieman von der Ruhr, Altenkamp fell to Gerhard Tiemann. For financial reasons, the latter sold Altenkamp in 1723 to the Drosten of the Emsland, Hermann Anton von Velen. At the beginning of the 18th century, the architect Peter Pictorius the Younger designed Haus Altenkamp and the park, which is surrounded by a moat. The alliance coat of arms of Hermann Anton von Velen with his first wife Anna Dorothea von Ascheberg zu Botzlar is located above the portal. The heiress daughter Anna Theresa von Velen married Clemens August von Landsberg, owner of Wocklum Castle, in 1756. Count Ignaz von Landsberg-Velen und Gemen sold the estate to the administrator Georg Behnes in 1856. For four generations, the estate was then owned by the Behnes family, who provided numerous lawyers, bailiffs or district councillors in Emsland, including Clemens August Behnes and his son Georg Behnes, and built up an extensive library and archive in their house, which is now accessible to the general public in the Lower Saxony State Archives - Osnabrück site. The property, which was purchased by the city in 1981, includes baroque gardens. In the rooms of the former manor house, exhibitions of the Prussian Cultural Heritage Foundation on art and cultural history topics are presented annually. In addition, concerts and public events organized by the Papenburg Cultural Circle are held in the gardens.