The origin of civilization is a political crisis. The burning of Athens makes Athens anew, but Themistokles belongs to old Athens, where already the democratic revolution had started. It is natural that the Spartans should fight the Persians, & on land, because the Spartans defend themselves & pray to their gods before battle & look for divine guidance in oracles more than anyone else. One could say, the gods they believe in are not Xerxes & the Persian gods.
But the cause of the wars & the most impressive fact about the war is the naval war fought by Themistokles, who reduced Athens to her navy, which he commanded, after the Athenians had fought at Marathon. The story hides the truth about Marathon: Miltiades was the great hero that day, savior of Athens, & father to a great political dynasty. In truth, Themistokles did not kill Darius. All this obfuscation means is, Themistokles shows us the future of Athens, which is also why the infamous end of Themistokles is concealed.
This future explains the meaning of freedom: Freedom is freedom from the gods & oracles, from divine laws & from the sacred limits on the city. That is why Themistokles says, he has no family. This is why he feels no compunction about breaking laws, tantamount to treason.
The new world brought into being by Themistokles is more sophisticated than the Persian: He knows empire must be godless. The men must fight for their city, but the very means of fighting transform the city – the navy, which is both defense & offense, both war & commerce, ever in motion. With Themistokles, there is no way back, but man must look for what the Persians looked: Man must reason about the cosmos to find what is good for him, without any thought to his ancestors or his mortality.
This may be a terrible curse. Athens, though a splendor, & the monument to the philosophers, nevertheless crumbled & was defeated by the Spartans, half-barbarian though they were. The Athenians used the Spartans successfully to achieve greatness, repeatedly profiting from the Spartan piety which kept Sparta from completely destroying Athens. But Athens could no longer replace Sparta than she could maintain an empire of freedom, rather enslaving everything she protected.
The promise of freedom brought forth by Themistokles is seen in the father dying & his son taking his place in the fight. The dying father frees the son to achieve for himself. Vengeance or justice is merely the prologue to this drama. Free men will not be free to choose to fight when once they are victorious. & the greatest fighters will not be rulers, nor receive the honor due to heroes.