Battle of Sempach
1386 CE.
Shown on the map at 47.146°, 8.213°.
The Battle of Sempach was fought on 9 July 1386, between Leopold III, Duke of Austria and the Old Swiss Confederacy. The battle was a decisive Swiss victory in which Duke Leopold and numerous Austrian nobles died. The victory helped turn the loosely allied Swiss Confederation into a more unified nation and is seen as a turning point in the growth of Switzerland.
Text from the Wikipedia article Battle of Sempach, licensed CC BY-SA 4.0.