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.

Already seriously ill, Emperor Lothair I staying at his estate in Schüller (Sconilare) on 19 September 855 further divided the Lotharii Regnum between his sons: Louis II († 875), the eldest son, was granted the imperial crown and the Kingdom of Italy (then only comprising the northern half of the Italian peninsula) Lothair II († 869) was granted Frisia and the parts of Austrasia that remained his father's after the Treaty of Verdun (containing the original area of the Roman Empire settled by the Franks and the capital of Aachen) - this kingdom became known as Lotharingia after its ruler and was the shortest-lived of the three successor kingdoms, succeeded by the duchies of Upper and Lower Lorraine about one hundred years later.

The effects of the Treaty of Prüm came to a complete end, when in 951 King Otto I of Germany invaded and conquered Italy during a period of political unrest and married the former queen consort Adelaide.

The Treaty of Prüm is regarded as one of the last significant effects of partible inheritance before being surpassed by feudalism as the primary cause of European state decentralization.