Complex sentence: Boeselager later offered to charge the Wolfsschanze with a full battalion of cavalry; this was rejected because of the extremely high casualties the unit would likely suffer and because it was impossible to transfer the unit from West Prussia to East Prussia.
Split into simpler sentences: Boeselager later offered to charge the Wolfsschanze with a full battalion of cavalry. It was rejected because of the extremely high casualties the unit would likely suffer and because it was also impossible to transfer the unit from West Prussia to East Prussia.