Duchy of Courland and Semigallia ( 1918 ) The Duchy of Courland and Semigallia was briefly a client state of the German Empire . It was proclaimed on 8 March 1918 , in German - occupied Courland Governorate by a " Landesrat " composed of Baltic Germans , who offered the crown of the once - autonomous Duchy to Kaiser Wilhelm II , despite the existence of a formerly sovereign reigning family in that duchy , the Biron descendents of Ernst Johann von Biron . Although the German Reichstag supported national self - determination for the Baltic peoples , the German High Command continued the policy of attaching the Baltic to the Reich by relying on Baltic Germans . In October 1918 , the Chancellor of Germany Prince Maximilian of Baden proposed to have the military administration in the Baltic replaced by civilian authority . After the German Revolution on 18 November 1918 , Latvia proclaimed independence and on 7 December , the German military handed over authority to the Latvian national government headed by Kārlis Ulmanis . Historical background . During World War I , the German Army had occupied the Courland Governorate of Russian Empire by the autumn of 1915 . A front was established along a line stretched between Riga , Daugavpils and Baranovitch . The Latvian National Council was proclaimed on 16 November 1917 . On 30 November , the Latvian National Council proclaimed an autonomous Latvian province within ethnographic boundaries , and a formal , independent Latvian republic was declared on 15 January 1918 . After the Russian Revolution , German troops started advancing from Courland , and by the end of February 1918 the territories of the former Russian Governorate of Livonia and Autonomous Governorate of Estonia that had declared independence were also occupied and fell under the German military administration . With the Treaty of Brest - Litovsk on 3 March 1918 Bolshevist Russia accepted the loss of the Courland Governorate and by agreements concluded in Berlin on 27 August 1918 the Autonomous Governorate of Estonia and the Governorate of Livonia were severed from Russia . As a parallel political movement under the German military administration , Baltic Germans began a process of forming provincial councils between September 1917 and March 1918 . The Duchy of Courland and Semigallia was proclaimed on 8 March 1918 by one such " Landesrat " composed of Baltic Germans , who offered the crown of the Duchy to Kaiser Wilhelm II . On October 1918 , the Chancellor of Germany Prince Maximilian of Baden proposed to have the military administration in the Baltic replaced by civilian authority . The new policy was stated in a telegram from the German Foreign Office to the military administration of the Baltic : " The government of the Reich is unanimous in respect of the fundamental change in our policy towards the Baltic countries , namely that in the first instance policy is to be made with the Baltic peoples . " On 18 November 1918 , Latvia proclaimed its independence . On 7 December 1918 the German Military handed over authority to the Latvian national government headed by Kārlis Ulmanis Recognition . Kaiser Wilhelm recognised the creation of Courland , as a German vassal by writing to Courland ' s " Landesrat " on March 8 , 1918 ( in German ) : Disestablishment . The United Baltic Duchy was nominally recognized as a sovereign state by the Kaiser only on September 22 , 1918 , half a year after Soviet Russia had formally relinquished all authority over its former Imperial Baltic provinces to the German Empire in the Treaty of Brest - Litovsk . After World War I , Courland became a part of the newly formed nation of Latvia , November 18 , 1918 .