メルセン条約
Shortly before his death in 855, Emperor Lothair I in turn divided his realm among his three sons in accordance with the Treaty of Prüm. His Burgundian heritage would pass to his younger son Charles of Provence (845–863). Then in 869 Lothair I's son, Lothair II, died without legitimate children, and in 870 his uncle Charles the Bald and Louis the German by the 870 Treaty of Meerssen partitioned his territory: Upper Burgundy, the territory north of the Jura mountains ("Bourgogne Transjurane"), went to Louis the German, while the rest went to Charles the Bald. By 875 all sons of Lothair I had died without heirs and the other Burgundian territories were held by Charles the Bald.