Lotharingia (Latin: regnum Lotharii, regnum Lothariense, Lotharingia, French: Lotharingie, German: Reich des Lothar, Lotharingien, Mittelreich) was a short-lived medieval successor kingdom of the Carolingian Empire. As a more durable later duchy of the Ottonian Empire, it comprised present-day Lorraine (France), Luxembourg, Saarland (Germany), the eastern half of Belgium and the southern half of Netherlands, along with parts of today's North Rhine-Westphalia (Germany), Rhineland-Palatinate (Germany) and Nord (France). It was named after King Lothair II, who received this territory after his father Lothair I's kingdom of Middle Francia was divided among his three sons in 855.[1]

Kingdom of Lotharingia / Duchy of Lotharingia
The Kingdom of Lotharingia (purple) and other Carolingian kingdoms following the Treaty of Prüm, 855
Common languagesOld Franconian, Old Frisian, Old Dutch, Old High German, Old Saxon, Old French, Yiddish, Medieval Latin
Western Christianity
King or Duke 
Lothair II
Bruno the Great
Historical eraMedieval
Preceded by
Succeeded by
Middle Francia
Lower Lotharingia
Duchy of Lorraine
Duchy of Swabia

Lotharingia resulted from the tripartite division in 855 of the kingdom of Middle Francia, which itself was formed after the threefold division of the Carolingian Empire by the Treaty of Verdun of 843. Conflict between East and West Francia over Lotharingia was based on the fact that these were the old Frankish homelands of Austrasia, so possession of them was of great prestige.