A part of the Grand Duchy of Posen from 1815 on, the town was again incorporated into the Prussian Province of Posen in 1848. According to the 1919 Treaty of Versailles, Fraustadt remained under German rule and formed the southernmost district of the Posen-West Prussia border province. Fraustadt was one of the few areas within Germany attacked by the Polish military during the Polish Defensive War in 1939 (or Polish Campaign'1939). For a few hours its neighboring town of Geyersdorf was the first German town to be occupied by enemy forces in the war. The other notable attack was carried on the same day by one PZL.23B of the 21st Squadron; the factory in Ohlau was the first victim of bomb attack onto the German territory. Fraustadt was occupied by Red Army in 1 February 1945. Since 1945 the area as a result of the 1945 Potsdam Conference belongs to Poland.