Lothar I was a Frankish king who ruled from 840 to 855 AD. He was the eldest son of Louis the Pious and inherited a portion of the Carolingian Empire after the death of his father. Lothar's reign was marked by conflicts with his brothers, Charles the Bald and Louis the German, as they vied for control over their father's territories. Lothar is best known for the Treaty of Verdun in 843, which divided the empire into three parts, laying the foundation for modern-day France and Germany. He ruled over the central portion, known as Lotharingia, which included parts of present-day Belgium, Netherlands, and Italy.