sep 7, 1812 - Napoleon is Defeated at Battle of Borodino
The Battle of Borodino led to the devastation of Napoleon's army at the hands of not only the Russian army, but also the Russian winter and the starvation that came with it. The weakening of Napoleon's stance alloted more power to the other European powers, allowing them to exile Napoleon at his refusal to return France to its historical size.
Added to timeline:
French Revolution and Napoleon