 The Carolingian rulers did not give up the traditional Frankish (and Merovingian) practice of dividing inheritances among heirs, though the concept of the indivisibility of the Empire was also accepted.The Carolingians had the practice of making their sons minor kings in the various regions ("regna") of the Empire, which they would inherit on the death of their father, which Charlemagne and his son Louis the Pious both did for their sons.Following the death of the Emperor Louis the Pious in 840, his surviving adult sons, Lothair I and Louis the German, along with their adolescent brother Charles the Bald, fought a three-year civil war ending only with the Treaty of Verdun in 843, which divided the empire into three "regna" while according imperial status and a nominal lordship to Lothair who, at 48, was the eldest.