The locality of Rogozno-Zamek lies between Grudziadz and Lasin. The ruins of a Teutonic Order castle tower on a hillock above the mouth of the river Gardega into the Osa. The selection of a site convenient for erecting a fortification was determined by the outstanding defensive properties of the lay of the land. The construction of a brick castle in Rogozno was commenced after 1275, on the site of an earlier wooden fortification. From 1285 the castle was manned by Teutonic Knights, headed by commander (komtur) Winand. In 1335 the 'komturia' (area administered by the komtur) was replaced by a 'wojtostwo' (area administered by a 'wojt'/commune head/). In 1466-1590 the castle was the seat of the local 'starosta'. After 1772 a large part of the buildings was demolished to serve as a source of building material necessary for raising a Prussian fort in Grudziadz. In 1934 the ruins of Rogozno Castle were recognised as an historical monument. Work on protecting the object was inaugurated in 1911. The plan of the upper castle was recreated in the course of archaeological research conducted in 1941-1942 under the supervision of H. Jacobi. The mediaeval castle was composed of three parts: the castle proper, the upper castle standing on top of the hill, the middle castle with a tall gate tower, and a sprawling forecastle on a neighbouring elevation, separated from the main fortification by a moat. The upper castle included four wings, and was encircled by outer walls. The western part of the hill features scarce preserved fragments of the upper castle walls. The grounds of the inner forecastle contain an extant square, five-storey gate tower, originally preceded by a gate gorge, and a bridge leading to the non-residential part of the forecastle. Another surviving element is a long fragment of the outer wall with a corner turret built on a circular plan. Today, the castle is considerably devastated due to natural destruction, efforts to obtain building material, and incorrect exploitation. Only a part of the object, which urgently calls for additional protection measures, is suitable for reconstruction.