Northern March

The Northern March or North March (, or ''marchia septentrionalis''; , ) was a frontier province (''march'') of the Holy Roman Empire, centered on the middle Elbe and encompassing regions of Polabian Slavs towards the east, up to the middle Oder. Initial jurisdictions at the Eastphalian (eastern Saxon) sections of the Elbe border were established already at the beginning of the 9th century, when Charlemagne appointed Odo, an eastern Saxon commander, as legate in charge of the frontier region on Elbe (in later Altmark). The expansion over the Elbe was intensified by the middle of the 10th century, when Gero I (d. 965) was appointed margrave (frontier count) over the subdued Slavic regions (thus the term: ''March of Gero''), but that jurisdiction was later divided, after his death, when count Dietrich of Haldensleben was appointed margrave and tasked to defend northeastern Eastphalian regions (including Altmark), while also being placed in charge over the pacification of neighboring Slavic tribes over the Elbe river, such as Hevellians and Redarians. Most of those gains were lost after the Slavic uprising of 983, while Dietrich's successors kept the frontier foothold on the middle Elbe, defending northern regions of Eastphalia (later known as ''Altmark'') and governing as margraves of the ''Northern March'', known under that name only since the 11th century. Effective German control over Slavic tribes to the east was reestablished by the middle of the 12th century, when the new March of Brandenvurg was established in those regions. Provided by Wikipedia