premise: Otto I, Holy Roman Emperor was defeated by the Magyars.
hypothesis: Otto I, Holy Roman Emperor . After putting down a brief civil war among the rebellious duchies , Otto defeated the Magyars at the Battle of Lechfeld in 955 , thus ending the Hungarian invasions of Western Europe . The victory against the pagan Magyars earned Otto a reputation as a savior of Christendom and secured his hold over the kingdom .