Saxe-Weimar
Charles Augustus joined Prussia in the Napoleonic Wars.  After France won the Battle of Jena, Saxe Weimar was forced to join the Confederation of the Rhine in 1806. In 1809 Saxe-Weimar and Saxe-Eisenach, which had been separate duchies with the same duke became one country as the Duchy of Saxe-Weimar-Eisenach.