Siege of Santarém
1184 CE.
Shown on the map at 39.237°, -8.685°.
The Siege of Santarém occurred in 1184 when the Almohad Caliph, Abu Yaqub Yusuf, unsuccessfully attempted to capture the fortified Portuguese city of Santarém. The operation failed due to misinterpreted orders and confusion which ultimately resulted in the death of Abu Yusuf.
Text from the Wikipedia article Siege of Santarém (1184), licensed CC BY-SA 4.0.