The Battle of the Unstrut River is said to have been fought in 531 CE near the river Unstrut when the king of Francia, Theuderic I decisively defeated the Thuringii army led by their king Hermanfrid. Thuringia was subjugated in 530 CE, soon after the battle.[1]
Durant, Will. The Age of Faith: A History of Medieval Civilization from Constantine to Dante -- A.D. 325-1300. The Story of Civilization IV. New York: Simon and Schuster, 1950. ISBN978-0-9650007-5-8.