Old Prussians
The Slavs had been moving in on the Old Prussians but had been stopped by them. The different duchies made hypocritical claims to lands they never controlled and invited the Teutonic Order to suppress "rebellions" there. It is possible therefore that the Kashubian Duchy of Gdańsk was asserting a nominal claim over Lake Drużno and Truso, but it was never one recognized by the Old Prussians.