Duchy of Cleves
Frederick William and Leopold, the "Old Dessauer", entrusted Dossow with the creation and training of new regiments during an expansion of the Prussian Army. Dossow was steadily promoted through the ranks: "Oberst" in 1728, "Generalmajor" and commander in 1733, and Acting Governor of Wesel in the Duchy of Cleves in 1739. During a visit to the duchy, King Frederick II promoted Dossow to "Generalleutnant".