Duke of Courland and Semigallia

Duchy of Courland and Semigallia
Ducatus Curlandiæ et Semigalliæ (la) Kurzemes un Zemgales hercogiste (lv) Księstwo Kurlandii i Semigalii (pl) Herzogtum Kurland und Semgallen (de)
Vassal state of Poland–Lithuania (1561–1726)
1561–1795
Flag Coat of arms
The Duchy of Courland and Semigallia in 1740.
Capital		Mitau
Languages		German, Latvian, Livonian, Latgalian
Religion		Lutheran, Roman Catholic
Government		Monarchy
Duke
•	1561–1587	Gotthard Kettler (first)
•	1769–1795	Peter von Biron (last)
Legislature		Diet
History
•	Treaty of Vilnius	28 November 1561
•	Colonial acquisitions	1637–1690
•	Partition of Poland	28 March 1795
Area
•	1870	27,286 km² (10,535 sq mi)
Population
•	1870 est.	619,154
Density		22.7 /km²  (58.8 /sq mi)
•	1897 est.	674,437
Density		24.7 /km²  (64 /sq mi)
Currency		Thaler
Preceded by Succeeded by Bishopric of Courland Livonian Order Courland Governorate
Today part of		Latvia
Adjective: Couronian, Courish, or Courlandish Demonym: Courlander or Couronian

Demonym: Courlander or Couronian

The Duchy of Courland and Semigallia (Latin: Ducatus Curlandiæ et Semigalliæ, Polish: Księstwo Kurlandii i Semigalii, German: Herzogtum Kurland und Semgallen, Latvian: Kurzemes un Zemgales hercogiste) was a duchy in the Baltic region that existed from 1561 to 1569 as a vassal state of the Grand Duchy of Lithuania and from 1569 to 1726 the Polish-Lithuanian Commonwealth, incorporated into the Polish-Lithuanian Commonwealth by Sejm in 1726, On 28 March 1795, it was annexed by the Russian Empire in the Third Partition of Poland.

There was also a short-lived wartime state existing from 8 March to 22 September 1918 with the same name. Plans for it to become part of the United Baltic Duchy, subject to the German Empire, were thwarted by Germany's surrender of the Baltic region at the end of the First World War. The area became a part of Latvia at the end of World War I; see Duchy of Courland and Semigallia (1918).

In 1561, during the Livonian Wars, the Livonian Confederation was dismantled and the Livonian Brothers of the Sword, an order of German knights, was disbanded. On the basis of the Treaty of Vilnius, the southern part of Estonia and the northern part of Latvia were ceded to the Grand Duchy of Lithuania and formed into the Ducatus Ultradunensis (Pārdaugavas hercogiste). The part of Latvia between the west bank of the Daugava River and the Baltic Sea became the Duchy of Courland and Semigallia, nominally a vassal state of the King of Poland Ruled by the Dukes from the House of Kettler with the exception of Peter von Biron