The Final Partition of the Carolingian Empire and the Outbreak of Civil War (839–840)

Throughout his long reign, Louis the Pious seeks to divide his empire fairly among his sons, adhering to Frankish traditions of partible inheritance as outlined in Salic Law. However, his decision to grant land to his youngest son, Charles the Bald, born from his second marriage to Judith of Bavaria, sparks decades of civil war among his older sons.

The Final Partition of 839: The Division at Worms

Following his vindicating victory over his last rebellious son, Louis the German, in 839, Emperor Louis the Pious divides his empire for the last time at Worms on May 30, 839:

• Lothair I → Retains Italy and the imperial title, along with all the other lands of the east, consolidating his claim as primary ruler of the empire.
• Charles the Bald → Receives all the lands of the west, ensuring a powerful Frankish kingdom that will later evolve into France.
• Louis the German → Left with only Bavaria, significantly reducing his authority.
• Pepin II of Aquitaine (son of the late Pepin I) → Excluded from the inheritance, fueling his discontent.

This arrangement favors Charles and Lothair, sidelining Louis the German and Pepin II, setting the stage for another civil war upon Louis the Pious’ death in 840.

The Death of Louis the Pious and the Civil War (840–843)

On June 20, 840, Louis the Pious dies, and almost immediately, Lothair I attempts to assert full imperial control, violating the agreements of Worms (839).

• On July 24, 840, in Strasbourg, Lothair declares his imperium over all Frankish lands, claiming overlordship over his brothers.
• He allies with his disinherited nephew, Pepin II of Aquitaine, and together they invade the Loire Valley, launching a campaign against Charles the Bald.