Do they have to do with a shift in the balance of power?
2- Greeks rise at the expense of the Persians.
3- Moors finally lose to Franks.
4- Basically the very beginning of the proof that colonies can stand against their rulers.
5- Napoleon could actually be stalled, if not defeated.
6- Kinda unsure about this one, after it, troops weren't mobile again until WW2, but then, it was only the Germans who had mastered the art.
EDIT: Another name for Jerusalem is Zion.
They're all final stands. Victorious or not. (Well, some of 'em, kinda.)
1-Already explained
2- Persians last chance to really prove they're better than Greeks.
3- Franks last to stand for Christianity.
4- One that doesn't seem to fit
5- Russians last to oppose Napoleon on the continent.
6- Another that doesn't seem to fit.