Charlemagne spent much of his reign as king of the Franks, (a Germanic tribe) engaged in warfare in order to accomplish his goals. He embarked on a mission to unite all Germanic peoples into one kingdom, and convert his subjects to Christianity. the empire he created was the Carolingian Empire.
"Human sacrifice and expansion of the empire" would be the best option from the list, although it should be noted that some of the expansion had begun before his reign officially began.
