Lothair I was a Frankish king who ruled from 840 to 855 AD. He was the eldest son of Louis the Pious and Judith of Bavaria. Lothair became the Emperor of the Romans in 855 and was known for his attempts to maintain unity among the territories of the Carolingian Empire. His reign was marked by conflicts with his brothers, Charles the Bald and Louis the German, over the division of their father's kingdom. The Treaty of Verdun in 843 divided the empire into three parts, with Lothair receiving the central region, known as Lotharingia.