Contention over the division of the Holy Roman Empire between the three surviving sons of Louis the Pious culminated in a decisive battle fought at Fontenay on the June 25, 841.

In spite of his personal gallantry, Lothair was defeated by his brother Louis the German, and half-brother Charles the Bald and fled to his capital of Aix-la-Chapelle (Aachen). With fresh troops he entered upon a war of plunder, but the forces of his brothers were too strong for him, and taking with him such treasure as he could collect, he abandoned to them his capital.

Initial text adapted from the entry for "Lothair I" in the 1911 Encyclopedia. Please update as needed.