Itzehoe is a town and a district-name around it in north-west direction of Hamburg. The area of district adjoins to Elbe-river, but the town is inland. Ploen is a town, a lake (Ploener See) and a district-name around it. Position is north-east of Hamburg between the cities Kiel and Luebeck.
Bell castle, then he unterstood Klingenburg (with u), may be ...berg and ...burg sounds similary if spoken English. In relation to Klingenberg the Name Klingenburg is seldom in Germany.