The territory on both sides of the Oder river formed the southeastern part of the Prussian kingdom. It comprised the bulk of the former Bohemian crown land of Upper and Lower Silesia as well as the adjacent County of Kladsko, which the Prussian King Frederick the Great had all conquered from the Austrian Habsburg Monarchy under Empress Maria Theresa in the 18th century Silesian Wars. It furthermore included the northeastern part of Upper Lusatia around Görlitz and Lauban, ceded to Prussia by the Kingdom of Saxony according to the resolutions of the Vienna Congress in 1815.