Battle on land
This is the imagery most famously associated with Sparta and their army. Their entire civilization is oriented around absolute power on the battlefield. They are groomed for this and trained their whole lives in the art of military strategy and hand-to-hand combat. Their absolute mastery of physical combat makes Athens very unlikely to engage them on land, though, because whenever they do battle on the land, Sparta has a strong advantage.
Battle at sea
The imagery that shapes Athenian combat is warfare from the sea. They evacuate their towns to the coast and fervently defend their port cities. Since they have a strong navy, they are immune from siege, because they can just travel through the ocean to battle, or to gather supplies abroad, and when the Spartans are lined up on the land, there is very little they can do to fight the Athenian navy. The sea is a natural force, so Athens is aligning themselves with nature in a powerful way.
The imagery of trickery
The imagery of Athens undermining Sparta's military advantages is well worth studying. The imagery of this is absolutely delightful. The expression of wit beating brute force is never more clear than when the Spartans invade cities to find them already evacuated. They try city after city just to find that their entire military strategy has been cleverly defeated. The imagery of trickery shows that sometimes, it is best to defeat an enemy without indulging them in combat.
Paranoia from ongoing threat
From a history book, someone might get the wrong idea that once a war is over, it's over and everyone goes home happy. That is far from the truth described in this History. The paranoia of war continues on both sides, and the distrust caused by violence continues into the future as well. The Spartans and Athenians are both more likely to fight in the future, and though they manage to come up with some peace treaties, it's only a few years until their agreement falls apart. The depiction of paranoia is helpful in war, because it gives foresight, but damaging to peace.
