The first Battle of Lechfeld, fought on 12 June 910, was an important victory by a Hungarian army over the combined forces of East Francia and Swabia (Alamannia) under the nominal command of Louis the Child. Located approximately 25 km (15.53 mi) south of Augsburg, the Lechfeld is the floodplain that lies along the river Lech. At this time the Grand Prince of the Hungarians was Zoltán, but there is no record of him taking part in the battle. After the battle, the victorius Hungarians broke into Franconia for the first time. On 22 June in Franconia, the same Hungarian army defeated a united army of the duchies of Franconia, Lotharingia and Bavaria in the Battle of Rednitz. The Bavarian, Frankish, Swabian and Saxonian duchies became taxpayers of the Hungarians. As consequence of this victory, in the next year, Hungarian attacks launched from the Carpathian Basin crossed the Rhine for the first time in 911.

Louis the Child, sometimes called Louis III or Louis IV, was the king of East Francia from 899 until his death and was also recognized as king of Lotharingia after 900. He was the last East Frankish ruler of the Carolingian dynasty. He succeeded his father, Arnulf, in East Francia and his elder illegitimate half-brother Zwentibold in Lotharingia.