Treaty of Prüm

The Treaty of Prüm, concluded on 19 September 855, was the second of the partition treaties of the Carolingian Empire. As Emperor Lothair I was approaching death, he divided his realm of Middle Francia among his sons.

From 830, Lothair and his brothers Pepin I of Aquitaine and Louis the German had fought several inner dynastic battles with their father Emperor Louis the Pious. The emperor's death in 840 started another fight for the inheritance between his three surviving sons Lothair I, Louis the German, and Charles the Bald. Lothair, eldest son and co-ruling Holy Roman Emperor with his father since 817, claimed supremacy but was denied and defeated by the united forces of his brothers at the 841 Battle of Fontenoy

Emperor Lothair finally had to yield the superior strength of Louis the German and Charles the Bald, who confirmed their pact by the Oaths of Strasbourg. He concluded his fighting and in August 843 signed the Treaty of Verdun with his younger brothers. As a result of this treaty, the empire of late Louis the Pious ("Francia") was officially divided between his three surviving sons: Louis the German received the lands east of the Rhine and Aare rivers ("East Francia"), Charles the Bald the territories west of the Scheldt, Meuse, Saône, and Rhône ("West Francia"), while Lothair retained the interjacent lands from Frisia to Italy, including the cities of Aachen and Rome ("Middle Francia" or Lotharii Regnum), and the title of Holy Roman Emperor.

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