Frederick Augustus I of Saxony in the context of "List of Lithuanian monarchs"

The Duchy of Warsaw (Polish: Księstwo Warszawskie; French: Duché de Varsovie; German: Herzogtum Warschau), also known as the Grand Duchy of Warsaw and Napoleonic Poland, was a French client state established by Napoleon Bonaparte in 1807, during the Napoleonic Wars. It initially comprised the ethnically Polish lands ceded to France by Prussia under the terms of the Treaties of Tilsit, and was augmented in 1809 with territory ceded by Austria in the Treaty of Schönbrunn. It was the first attempt to re-establish Poland as a sovereign state after the 18th-century partitions and covered the central and southeastern parts of present-day Poland.

The duchy was held in personal union by Napoleon's ally, Frederick Augustus I of Saxony, who became the duke of Warsaw and remained a legitimate candidate for the Polish throne. Following Napoleon's failed invasion of Russia, Napoleon seemingly abandoned the duchy, and it was left to be occupied by Prussian and Russian troops until 1815, when it was formally divided between the two countries at the Congress of Vienna. The east-central territory of the duchy acquired by the Russian Empire was subsequently transformed into a polity called Congress Poland, and Prussia formed the Grand Duchy of Posen in the west. The city of Kraków, Poland's cultural centre, was granted "free city" status until its incorporation into Austria in 1846.