I have some information on Kronprinzenkoog.... Kronprinzenkoog is a Koog in Sderdithmararschen west of Marne. The Koogdistrictof the United Kronprinzenkoog, Sophienkoog and Konig Friedrichkoog. My Grand mother Bols, Irene was born & baptist in Friedrichskoog b. 28 Jan 1875. I have the church boptiism record from the Lutheran Church in Friedrichenkoog If can be if any more help contact me direct [email protected]