Um, quite a complicated (…and almost political) subject.
3. Tours – ended the expansion of Islam within Europe with a profound impact on European culture.10. Moscow – taking the capital, its manufacturing resources, communications hub and political significance might have been a blow
I’m not sure that the battle at Tours (or Poitiers) was something more than defeating a mere raid. This victory helped the renown of the Frankish dynasty at the time, and was celebrated later, but it was probably not a real invasion.
that was EXACTLY what I was gonna say. Replace it with one of Alexander’s battles. Turning Anatolia and beyond into Greek lands for several thousand years must count as quite important. 3. Gaugemala