Lotharii Regnum
Middle Francia was situated between the realms of East and West Francia, and comprised the Frankish territory between the rivers Rhine and Scheldt, the Frisian coast of the North Sea, the former Kingdom of Burgundy (except for a western portion, later known as "Bourgogne") and Provence, as well as parts of northern Italy. Following the 855 partition, 'Middle Francia' became only a geographic term and the bulk of its territory was reorganized as Lotharingia, named after Lothair I's namesake son.