Historians aren t sure why people during medieval times used the tunnel, but they believe that the Nazis may have used it for shelter and storage.
From 1121 to 1637, the Griffin dynasty ruled the Duchy of Pomerania from Ducal Castle. They erected several castles, but Ducal Castle was the most important among them.
Ducal Castle was constructed under Barnim III, Duke of Pomerania, in 1345, who ruled Pomerania-Stettin from 1344-1368. He co-ruled the Duchy with his father, Duke Otto I, until 1344, when his father passed.
Then Barnim III became the sole leader and during his reign he aimed to make the duchy independent of Brandenburg, Germany. In 1348 he achieved his goal with the help of Charles IV of Luxembourg . This alliance strengthened the political position of the duchy but created additional conflict with Brandenburg.