Lothair I
Lothair I, (French: Lothaire,)(795?–855), a medieval Frankish emperor. He was the son of Emperor Louis I and the grandson of Charlemagne. In 817 Lothair was made co-emperor with his father, but he lost the title in 829. For the next decade he was frequently in revolt against Louis, twice defeating him and temporarily taking the title of emperor before being defeated by Louis' allies. After Louis died in 840, war broke out between Lothair and his brothers Louis and Charles. In 843 the three brothers divided the realm in the Treaty of Verdun. Lothair retained the imperial title that he had inherited at Louis I's death, and kept the middle part of the empire, a section of which was later called Lotharingia, from which the name Lorraine is derived. Lothair's part of the empire included parts of what are now rance, the Netherlands, Belgium, Switzerland, and Italy.