As the first non-Frankish king of East Francia, Henry the Fowler established the Ottonian dynasty of kings and emperors, and he is generally considered to be the founder of the medieval German state, known until then as East Francia.
Henry was elected and crowned king in 919. Henry built an extensive system of fortifications and mobile heavy cavalry across Germany to neutralize the Magyar threat and in 933 routed them at the Battle of Riade, ending Magyar attacks for the next 21 years and giving rise to a sense of German nationhood.
Henry greatly expanded German hegemony in Europe with his defeat of the Slavs in 929 at the Battle of Lenzen along the Elbe river, by compelling the submission of Duke Wenceslaus I of Bohemia through an invasion of the Duchy of Bohemia the same year and by conquering Danish realms in Schleswig in 934. Henry's hegemonic status north of the Alps was acknowledged by the kings Rudolph of West Francia and Rudolph II of Upper Burgundy, who both accepted a place of subordination as allies in 935.