Numerous legends and myths surround the Battle of Tannenberg in 1410, as this military conflict can be compared in significance to the Battle of Stalingrad in World War II for the state of the Teutonic Order. But what really happened on July 15, 1410? This volume intensively examines all the relevant factors that influenced the outcome of this confrontation: causes of the war, protagonists, course of the war, balance of power, troop strengths, equipment, plans, objectives, and the progression of the battle. The battle is described in the context of the historical events from 1409 to 1411, including the defense of Marienburg. Additionally, the development of the Teutonic Order before and after the battle is briefly outlined to clarify the significance of the conflict. To complete the picture, an appendix includes a list of the participants by name.