Battle of Varna
1444 CE.
Shown on the map at 43.217°, 27.883°.
The Battle of Varna took place on 10 November 1444 near Varna in what is today eastern Bulgaria. The Ottoman army under Sultan Murad II (who did not actually rule the sultanate at the time) defeated the Crusaders commanded by King Władysław III of Poland and Hungary, John Hunyadi (acting as commander of the combined Christian forces) and Mircea II of Wallachia. It was the final battle of the unsuccessful Crusade of Varna, a last-ditch effort to prevent further Ottoman expansion into the Balkans.
Text from the Wikipedia article Battle of Varna, licensed CC BY-SA 4.0.