Battle of Lechfeld
After the Hungarian conquest of the Carpathian Basin in the late 9th century, the Magyar horsemen dared further invasions into the adjacent West Frankish lands, until they were finally defeated by King Otto I in the 955 Battle of Lechfeld. Thereafter the forces of the Bavarian duke Henry the Wrangler gradually re-conquered the lands beyond the Vienna Woods up to the Leitha River, where about 976 the March of Austria ("Ostarrîchi") was established under the Babenberg margrave Leopold I.