West Francia
Charlemagne was succeeded by his son Louis the Pious. Even during Louis' life his three sons started fighting over his heritage. They eventually concluded multiple treaties, of which the Treaty of Verdun, signed in 843, would be the definitive treaty. These treaties created East Francia, Middle Francia and West Francia. West Francia, inherited by Charles the Bald, included the original county of Flanders, that spanned roughly between Oudenburg, Aardenburg and Torhout.