Docm30 said:
Although Napoleon exerted a great deal of influence over the Duchy, he didn't rule it. Not officially, at least. It was ruled by Frederick Augustus, Duke of Warsaw and King of Saxony. The Duchy was never ruled by Prussia because it was only created in 1807 by Napoleon out of former territories taken from Prussia and Austria.
+1
>>> silentdeath838
"The Duchy of Warsaw (Polish: Księstwo Warszawskie; French: Duché de Varsovie; German: Herzogtum Warschau; Russian: Варшавское герцогство, Varshavskoye gertsogstvo) was a Polish state established by Napoleon I in 1807 from the Polish lands ceded by the Kingdom of Prussia under the terms of the Treaties of Tilsit. The duchy was held in personal union by one of Napoleon's allies, King Frederick Augustus I of Saxony. Following Napoleon's failed invasion of Russia, the duchy was occupied by Prussian and Russian troops until 1815, when it was formally partitioned between the two countries at the Congress of Vienna."
for more: http://en.wikipedia.org/wiki/Duchy_of_Warsaw