The First Battle of Langensalza is fought on June 9, 1075, between forces of King Henry IV of Germany and several rebellious Saxon noblemen on the River Unstrut near Langensalza in Thuringia.
The battle is a complete success for Henry, resulting in the subjugation of the Saxons shortly before the Investiture Controversy commences in earnest.
In Germany, the battle is known as the Schlacht bei Homburg an der Unstrut, after a nearby Kaiserpfalz and monastery.