Oaths of Strasbourg by Charles and Louis

In 842, Charles the Bald and Louis the German swore mutual oaths to support each other against their brother, Lothair I, amidst the division of the Carolingian Empire. This significant act took place at Strasbourg, where both rulers expressed their commitment to unity in differing languages, underscoring their political alliance. The event not only highlighted the fractious nature of their relationship with Lothair but also set a precedent for cooperation among the splintered factions of the empire during a time of great familial and political strife.