Final answer:
Louis the Pious had three sons named Lothar, Louis the German, and Charles the Bald, who divided the Carolingian Empire among themselves following the Treaty of Verdun in 843.
Step-by-step explanation:
Louis the Pious's three sons were named Lothar, Louis the German, and Charles the Bald.
Following the division of the Carolingian Empire under the Treaty of Verdun in 843, the empire was split into three territories among the three brothers. The Kingdom of the West Franks was given to Charles the Bald, the Kingdom of the East Franks to Louis the German, and Lotharingia, the middle region that included Italy, fell to Lothar.
This division was part of the principle of partible inheritance, which often led to conflict as each generation's holdings became fragmented and diminished.