Siege of Constantinople
1260 CE.
Shown on the map at 41.012°, 28.976°.
The siege of Constantinople in 1260 was the failed attempt by the Nicene Empire, the major remnant of the fractured Byzantine Empire, to retake Constantinople from the Latin Empire and re-establish the City as the political, cultural and spiritual capital of a revived Byzantine Empire.
Text from the Wikipedia article Siege of Constantinople (1260), licensed CC BY-SA 4.0.