Upon the death of Charlemagne's son, Louis the Pious,
A.The empire was divided between Louis's three sons, Charles the Bald, Louis the German, and Lothar.
B.A Viking army from Norway conquered the whole empire and the leader of the Norse army, Joakim Brodén, made himself emperor.
C.The empire passed to his heir Theophilus, who as the son of Louis and his wife, the Byzantine princess Theophanu, became ruler of both the Carolingian and Byzantine Empires.
D.The Carolingian Empire was passed on to Louis's only surviving son, Louis the German.