independent Polish state created by Napoleon (Napoleon I). It became a focal point of efforts to restore the Polish nation, which had been destroyed by the partitions of Poland (Poland, Partitions of) made by Russia, Prussia, and Austria in 1772, 1793, and 1795.

Established by the Treaties of Tilsit (July 7 and 9, 1807) after the Poles had helped Napoleon defeat Prussia, the duchy consisted originally of the major portion of the central Polish provinces that had been absorbed by Prussia in 1793 and 1795. Exceptions were Danzig (Gdańsk), which became a free city; the district of Białystok, which was ceded to Russia; and the region of the Noteć (German Netze) river, acquired by Prussia in 1772, which was added to the duchy. In 1809 the duchy was increased by the territory that Austria had seized in the third partition.

Shortly after the Duchy of Warsaw had been founded, Napoleon (Napoleon I) dictated its constitution (July 22, 1807). It was framed on the French model and established a powerful executive branch of government, which was headed by Frederick Augustus I, the king of Saxony and grandson of Augustus III. The Napoleonic Code became the law of the duchy (May 1, 1808).

Poland's hopes for greater things revived once more when Napoleon announced his war against Russia (1812) as his “second Polish war.” The duchy, by an immense effort, put an army corps of nearly 98,000 men into the field. But the calamity that overtook Napoleon in Russia also sealed the fortunes of the duchy. The remainder of the Polish troops faithfully followed Napoleon in his campaign of 1813–14, during which the heroic leader of the Poles, Prince Józef Antoni Poniatowski, perished in covering the Emperor's retreat from Leipzig.

On Feb. 8, 1813, the Russians occupied Warsaw and assumed control of the duchy. Subsequently, the Congress of Vienna (Vienna, Congress of) determined that the Duchy of Warsaw was to be divided into three parts: the Grand Duchy of Poznań, which was returned to Prussia; the free Republic of Cracow (Kraków), which was placed under the protection of Russia, Prussia, and Austria; and the Congress Kingdom of Poland, which was joined to Russia by making the Russian emperor its king.