, 1635) shows the Queiß(e) Fl(uvius), now Kwisa marking its eastern border From about 937 the southeastern outskirts of the
Saxon Marca Geronis, established in the conquered lands settled by the West Slavic
Milceni tribes, reached to the left banks of the Queiß-Kwisa. After the partition of the march in 965, the lands west of the river belonged to the Imperial
Margravate of Meissen, while the adjacent territory to the east was gradually incorporated into the
Silesian region recently conquered by of the
Early Polish state under the
Piast duke
Mieszko I until 992. His successor
Bolesław I Chrobry further extended the Polish reach of power to the west, campaigning the Milceni lands around
Bautzen (
Budissin), which after several years of
German–Polish struggle Emperor
Henry II the Saint ceded to him according to the 1018
Peace of Bautzen. Nevertheless, the
Land Budissin, later called
Upper Lusatia, was reconquered by Emperor
Conrad II in 1031 and again held by the Meissen margraves until King
Henry IV of Germany in 1071 enfeoffed Duke
Vratislaus II of Bohemia, his ally in the looming
Saxon Rebellion. The Bohemian rule was again confirmed by Emperor
Frederick Barbarossa in favour of Duke
Vladislaus II in 1158, accompanied by the royal title. Meanwhile, the territory east of the Kwisa had been incorporated into the Polish
Duchy of Silesia in 1138, which after the Emperor's 1163 expedition to Poland was held by the
Silesian Piast descendants of Duke
Władysław II the Exile. From that time on the river marked the border between the historical regions of
Lower Silesia—i.e. the
Duchy of Legnica from 1248, the
Duchy of Jawor from 1274—in the east and Upper Lusatia in the west. Together with the lower Bóbr, the Kwisa was therefore one of the rivers considered as a possible marker of the Polish–
German border after
World War II during the negotiations at the 1945
Potsdam Conference, that finally led to the establishment of the
Oder–Neisse line about 50 km (30 mi) to the west. ==References==