Herzogtum Schlesien
However, the first confirmed mention of Racibórz was made in 1108 in the "Gesta principum Polonorum" chronicle by the Benedictine monk Gallus Anonymus, at a time when the Polish duke Bolesław III Wrymouth had to ward off the attacks by the forces of Duke Svatopluk of Bohemia invading from the Moravian lands in the south. The Polish rule over the Racibórz area was confirmed in 1137, it was incorporated into the Duchy of Silesia according to the Testament of Bolesław III in the following year.