Kammala jumla mai zuwa: A ranar 1 ga Maris, 1806, Deroy ya sami Babban Gicciye na Sojan Sojan Max Joseph. A cikin
Yaƙin Ƙungiyar ta huɗu, an sanya Deroy a ƙarƙashin umurnin Yarima Jerome Bonaparte. Ya yi kewaye da kewaye da sansanin soja na Prussian a Silesia a cikin 1806 da 1807. A watan Nuwamba na 1806, Rundunar Bavarian ta 1 ta Deroy ta kewaye sansanin soja na Głowgów (Glogau). Bayan an maye gurbin Bavarians da wani bangare na Württemberg, wurin ya mika wuya a ranar 2 ga Disamba. Ya yi tafiya zuwa Wrocław (Breslau) inda rabonsa ya isa a ranar 18 ga Disamba. Sojoji 22,000 na Yarima Jerome IX Corps sun ci gaba da kewaye har zuwa ranar 6 ga Janairu 1807 lokacin da sansanin soja ya ba da fursunoni 5,300 da bindigogi 268. Bavarian ya rasa rayuka 259 a cikin aikin. Deroy sai ya ci gaba tare da sojoji 13,000 don su kewaye Brzeg (Brieg). A ranar 17 ga Janairu Brzeg ya mika wuya tare da fursunoni 1,450.