Duke candidate for the planned United Baltic Duchy
At the end of the First World War, in the autumn of 1918, the Duke was offered the throne of the United Baltic Duchy, a short-lived client-state proclaimed on Baltic territories under German occupation.
By the Russo-German Treaty of Berlin (27 August 1918), Soviet Russia had formally relinquished all sovereignty over Baltic provinces of Estonia and Livonia, and on 22 September (1918), Germany formally recognized independence of those lands, that were effectively still under German military occupation.
By the autumn of 1918, the Duke was approached by Heinrich von Stryk, a representative of the Baltic German nobility, but final steps towards implementation of their plans were undertaken on 5 November, when representatives of Baltic Germans and some pro-German oriented leaders among Estonian and Latvian politicians from Courland, Livonia and Estonia met in Riga and proclaimed the creation of the United Baltic Duchy. Since the Duke was in Germany, the temporary regency council (Regentschaftsrat) was established in Riga, headed by baron Adolf Pilar von Pilchau, and consisting of three Baltic Germans, three Estonians and three Latvians. The newly proclaimed state was to be a union of seven cantons: Courland, Riga, Latgale, South Livonia (Südlivland, modern Vidzeme), North Livonia (Nordlivland, modern south Estonia), the Islands (Ösel, modern Saaremaa), and Estonia (Estland, modern north Estonia). Since Germany lost the War by 11 November, the Duke never assumed the Baltic throne. The newly created states of Estonia and Latvia emerged in the region, and the Baltic regency council functioned until 28 November 1918, when it was dissolved.
