An Austrian corps is defeated by the forces of the Duchy of Warsaw in the Battle of Raszyn

The Duchy of Warsaw 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.