Duchy of Warsaw Księstwo Warszawskie  (Polish) Duché de Varsovie  (French) Herzogtum Warschau  (German)
1807–1815
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The Duchy of Warsaw in 1812
Status	Client state of the French Empire, Personal union with the Kingdom of Saxony
Capital	Warsaw
Common languages	Polish, French, German
Religion	Roman Catholic
Government	Constitutional monarchy
Duke
• 1807–1815	Frederick Augustus I
Prime Minister
• 1807	Stanisław Małachowski
• 1807–1808	Ludwik S. Gutakowski
• 1808–1809	Józef Poniatowski
• 1809–1815	Stanisław K. Potocki
Legislature	Sejm
• Upper house	Senate
• Lower house	Chamber of Deputies
Historical era	Napoleonic Wars
•	9 June 1807
• Constitution	22 July 1807
• Battle of Raszyn	19 April 1809
• Treaty of Schönbrunn	14 October 1809
• Invasion of Russia	24 June 1812
•	9 June 1815
Area
• Total	Lua error in Module:Convert at line 1850: attempt to index local 'en_value' (a nil value).
Currency	Złoty
Preceded by Succeeded by South Prussia West Prussia New East Prussia Netze District West Galicia Congress Poland Grand Duchy of Posen West Prussia Free City of Cracow

The Duchy of Warsaw (Polish: Księstwo Warszawskie, French: Duché de Varsovie, German: Herzogtum Warschau) was a Polish state started by Napoleon Bonaparte in 1807 during the Napoleonic Wars. Poland had been divided among its neighbors in the Partitions of Poland. The Dutchy was made up of the Polish lands given to France by the Kingdom of Prussia under the terms of the Treaties of Tilsit. Prussian and Russian troops occupied it when Napoleon was defeated in Russia. This split was made official in 1815 at the Congress of Vienna.