In 909 a Hungarian army invaded Bavaria, but it was defeated by Arnulf, Duke of Bavaria in a minor battle near Pocking.

King Louis decided that forces from all the German duchies should come together to fight the Hungarians. He even threatened with execution those who would not gather under his flag. So we can presume that Louis gathered a "huge army," as Liutprand terms it in his Antapodosis. The exact size of the Frankish army is not known, but it can be assumed that it was far more numerous than the Hungarian army. This explains why the Magyars were so cautious during the battle, and waited an unusually long time (more than twelve hours), sapping the strength of the enemy little by little with hit-and-run tactics as well as using psychological methods to confuse them, before taking the decisive tactical step.

The first Battle of Lechfeld was an important victory by a Magyar army over the combined forces of East Francia and Swabia (Alamannia) under the nominal command of Louis the Child. This battle is one of the greatest examples of the success of the feigned retreat tactic used by nomadic warriors, and an example of the effective use of psychological warfare.