Assigned to lead a brigade in the VI Corps, he fought at Haslach-Jungingen and Dürrenstein in the War of the Third Coalition. He earned advancement to general of division on 24 December 1805 but continued to lead a brigade. The following year he fought at Halle, Waren-Nossentin, and Lübeck. In the last action he captured Carl Carlsson Mörner and 600 Swedes. In 1807, he served at Mohrungen and Braunsberg before being given command of a Hessian division. He then led, for some time, the forces besieging Graudenz.