Saxon Ostmark

The Saxon Eastern March (German: Sächsische Ostmark) was a march of the Holy Roman Empire from the 10th until the 12th century. The term "eastern march" stems from the Latin term marchia Orientalis and originally could refer to either a march created on the eastern frontier of the East Frankish duchy of Saxony or another on the eastern border of the Duchy of Bavaria: the Bavarian marchia Orientalis (documented as Ostarrîchi in 996), corresponding to later Austria.

The Saxon Ostmark initially referred to the vast Marca Geronis ('Gero's march'), established about 939 under the rule of King Otto I in the settlement area of the Polabian Slavs (Sorbs), beyond the Saxon Eastern border on the Elbe and Saale rivers. The conquered territories were governed by the Eastphalian legate Gero, count in the Nordthüringgau, who was vested with the Carolingian title of a margrave. It was his task to collect tributes and to overcome riots and revolts in the frontier areas, later partly superseded by Otto's Saxon deputy Hermann Billung. In 963, Gero in late age waged another military campaign against the Slavic Lusatian (Lusici) tribes, up to the border with the Polish lands ruled by Mieszko I.

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