Just a few days before his death in late autumn of 855, Emperor Lothair I divided his realm of Middle Francia among his three sons, a partition known as Treaty of Prüm.

On the death of his brother Charles in 863, Lothair added some lands south of the Jura to this realm, but except for a few feeble expeditions against the Norman pirates he seems to have done little for its government or its defense.

Although quarrels and reconciliations between the three kings followed each other in quick succession, in general it may be said that Louis favoured annulment, and Charles opposed it, while neither lost sight of the fact that Lothair had no sons to inherit his lands.

Still pursuing his purpose, he won the support of his brother, Emperor Louis II, by a cession of lands and obtained the consent of the local clergy, such as Adventius of Metz, to the annulment and to his marriage with Waldrada, which took place in 862.

An attack on Rome by the emperor was without result, and in 865 Lothair, threatened with excommunication and convinced that Louis and Charles at their recent meeting had discussed the partition of his kingdom, again took back his wife.