Srebrenik Fortress is Bosnia's best-preserved medieval castle dating from 1333. It is located in the outskirts of Srebrenik. The castle was occupied by the Ban of BosniaStjepan Kotromanić until his death in 1353. It was once considerably larger but some of its walls and structure have since collapsed. Also it is known for a document called "Povelja of Stjepan II Kotromanić" in which Stjepan gifts islands around island of Labin to Republic of Dubrovnik which is controversial by many residents in Srebrenik. Gradina is the birthplace of Tvrtko I Kotromanić first king of Bosnia and Herzegovina.