波列斯瓦夫一世
Soon however, the German feudal rule was threatened by the ascending Polish kingdom and its western expansion. In 1002 Bolesław I Chrobry conquered both Upper and Lower Lusatia and forced German king Henry II to enfeoff him with the "Gau Milsca". After several volatile and bitter feuds both parties signed the Peace of Bautzen on 30 January 1018, which assigned the Milceni lands of Upper Lusatia and Lusatia proper (today Lower Lusatia) to Poland. After the victory of Emperor Conrad II over the Polish king Mieszko II Lambert in 1031, Upper Lusatia again came under the rule of the Meissen margraves, confirmed by the 1033 Treaty of Merseburg.