Can't remember who was the Greek author who said that, even if Sparta could beat Athens, nothing would remain of the former while the latter would be remembered for eternity. He wasn't wrong

You may be quoting Thuccidides who wrote (and participated in) the Peloponnesian war between Sparta and allies and Athens and allies. It lasted 10 years and was won by Sparta. 5 years after their defeat the Athenians re established their empire and navy.