Pope Adrian I asked him to defeat King Desiderius, which he did at the Siege of Pavia.  
Widukind escaped this king's slaughter of approximately 4,500 rebellious Saxons at the Massacre of Verden. Pope Adrian I asked him to defeat King Desiderius, which he did at the Siege of Pavia.  The Treaty of Verdun ended a civil war within his empire by settling a land dispute between the sons of (*) Louis the Pious. This loser at the Battle of Roncevaux Pass co-ruled with his brother Carloman as the second Carolingian emperor after the death of his father Pepin the Short. He was crowned by Pope Leo III as the first Holy Roman Emperor on Christmas 800 A.D. For 10 points, name this second king of the Franks.
Widukind escaped this king's slaughter of approximately 4,500 rebellious Saxons at the Massacre of Verden.
{Charlemagne} [or {Charles I} or {Charles the Great} or {Carolus Magnus} or {Karl der Grosse}] [MB]