Battle of Muhu
1227 CE.
Shown on the map at 58.583°, 23.173°.
The Battle of Muhu was a military engagement fought between a force of Baltic and Germanic crusaders and pagan Oeselians. The battle, fought in Muhu, Estonia, resulted in the crusaders storming and capturing a fortress held by the Oeselians.
Text from the Wikipedia article Battle of Muhu, licensed CC BY-SA 4.0.