Following the death Charlemagne’s son, Louis I, the Carolingian Empire was split between his three sons in keeping with the method of succession of the Old Frankish Kingdoms. Lothair, the eldest son, had attempted to claim sole leadership of the empire upon the death of his father who left him the imperial insignia. This prompted an alliance between the other two sons, Charles and Louis, who entered into a war with Lothair to defend their equal claims to the empire. Lothair was defeated in 841 and the brothers entered into negotiations to determine the division of the empire under the Treaty of Verdun. The treaty was signed in 843 and split the empire into three sections, which centred on areas in which the three brothers were already established. Lothair was allowed to keep the title of Holy Roman Emperor but did not have any power over either brother’s lands.