Bolesław I Chrobry
The area of Lower Lusatia roughly corresponds with the eastern March of Lusatia or Saxon Eastern March between the Saale and Bóbr rivers, which about 965 was severed from the vast "Marca Geronis", conquered by the Saxon count Gero in the course of his campaigns against the Polabian Slavs from 939 onwards. Odo I became the first margrave; his successor Gero II from 1002 onwards had to face several attacks by Polish duke Bolesław I Chrobry, which did not end until the 1018 Treaty of Bautzen, which ceded large parts of eastern Lusatia to Poland. Emperor Conrad II reconquered the territories in 1031.