His elder brothers had only daughters, so following Charles Eugene's death in 1793 and then that of their brother Duke Ludwig Eugen (1731–1795), Frederick Eugene became reigning duke until his own death two years later.[1] He acquiesced to the Treaty of Paris (7 August 1796) [de] with revolutionary France, in which his claims to Montbéliard and all other territories on the left bank of the Rhine River were renounced.[1] Frederick Eugene retained, however, France's recognition of the integrity of the Duchy of Württemberg itself.
Charles Henry (3 July 1772 – 28 July 1838), married under the name "Count von Sontheim" in 1798 Christianne-Caroline Alexeï (1779–1853), who was created Baroness von Hochberg und Rottenburg in 1807 and was raised, along with her children, to the rank and title of Countess von Urach on 12 November 1825. Of their five daughters three died young, while Countess Marie von Urach (1802–1882) wed Karl, Prince of Hohenlohe-Kirchberg (1780-1861) in 1821 and Countess Alexandrine von Urach (1803–1884) married Charles, Count Arpeau de Gallatin (1802–1877) in 1825, from whom she was divorced in 1843.