Battle of Giornico
1478 CE.
Shown on the map at 46.383°, 8.883°.
In the Battle of Giornico, also known as the battle of large rocks (Italian: Battaglia di Giornico, dei Sassi Grossi; German: Schlacht bei Giornico) (28 December 1478), about 600 Swiss troops ambushed from above and defeated a larger force of the Duchy of Milan, confined in a narrow icy valley, by rolling large boulders down the hillside against the Milanese.
Text from the Wikipedia article Battle of Giornico, licensed CC BY-SA 4.0.