Greece without a doubt influenced Rome, but the point I was making is that if Greece had been conquered, Rome woudn't have happened. That means no Roman Republic, no Catholic Church or Christianity, no Holy Roman Empire, etc. Missing those things would significantly change history even if people didn't realize it. No offense to the Iriquois but their existence (or lack of) probably wouldn't be noticed outside of what is today the eastern United States.
Without the naval victories by Themistocles Greece would have been overrun.