Battle of Suiyang
757 CE.
Shown on the map at 34.383°, 115.619°.
The siege of Suiyang was a military campaign during the An Lushan rebellion, launched by the rebel Yan army to capture the city of Suiyang from forces loyal to the Tang dynasty. Although the battle was ultimately won by the Yan army, it suffered major attrition of manpower and time. The siege was noted for the Tang army's determination to fight to the last man, as well as the large-scale cannibalism practised by the defenders, who in this way were able to hold out longer.
Text from the Wikipedia article Siege of Suiyang, licensed CC BY-SA 4.0.