A Persian prince had crossed over to the Greeks the previous evening, reporting that the strengthened Immortals are on their way to the Spartan rear. But the Spartans do not believe this. They believe it’s a trick. This “irrational and self-deluding response,” Xeo explains, must be understood not just in light of exhaustion, despair, or euphoria, but in the light of “marvels and prodigies.” After having survived 48 gruesome hours, the men are coming undone: “Existence had become a tunnel whose walls were death and within which prevailed no hope of rescue or deliverance.”
The Spartans have been under the pressures of battle for so long that they are no longer thinking clearly, beginning to see miraculous signs in everything—a clear sign of Dienekes’ dreaded katalepsis. This blindness will be disastrous for the battle as a whole.
On the evening of that day’s battle, the Persians cause the Spartans to fall back and even manage to pour beyond the Phokian Wall. Yet the Persians are stopped by inexplicable terror from pressing home their victory. Just then, “a bellow of unearthly power”—a lightning strike—hits Kallidromos, the mountain overlooking the sea. At this, King Leonidas calls out in praise of “Zeus Savior” and freedom. With fresh courage, the Spartans rush at the foe, causing them to tumble back in panic at this “prodigy of heaven.” There is a mayhem of retreating and advancing Persians, resulting in a grisly wall of bodies which eventually gives way in a horrifying avalanche.
The Spartans aren’t the only ones who are being overwhelmed by fear. The Persians almost overcome them, but a timely lightning strike causes the Spartans to recollect themselves and push back the advance. Even Leonidas interprets the strike as divine intervention.
Later that night, these events are “cited as evidence of the intercession of the gods.” Even as the benevolent Persian nobleman urges them to withdraw while there’s still time, the Spartans and allies are so exultant over the “prodigies” that they won’t stand down. What’s more, a storm has wrecked 200 Persian warships—surely the work of God as well. A Theban commander “[inflames] the derangement” by pointing out that the Persians’ conscripted army must be filled with disaffection by this time.
All these factors persuade the Spartans that they’re on a path to victory and shouldn’t withdraw, despite the Persian defector’s warnings. The “madness” keeps building on itself and pushing the Spartans into a situation from which they can’t recover.
The Greeks accordingly respond harshly to the Persian informer, telling him it’s Xerxes who’s in peril. Xeo knows what he’s seeing is katalepsis, “grief- and horror-spawned rage.” The Persian noble stays and talks with Leonidas, insisting that if the gods have a hand in all this, it’s “their perverse and unknowable will acting to detach [the Spartans] from their reason.” Surely Leonidas must be able to perceive this.
It’s the nature of katalepsis that it blinds people, even those as wise as Leonidas, from interpreting circumstances as they should. The circumstances could just as easily be interpreted as the gods’ attempt to trick the Spartans and lead them astray, but the Spartans are determined to see otherwise.
The Persian noble continues to appeal to Leonidas. He warns him that Thermopylae won’t be the decisive battle. Greece needs Leonidas, he says. While Leonidas claims a Spartan king never retreats, his “valor must be tempered with wisdom or it is merely recklessness.” He and his men have already won great fame by holding out for six days. Surely it’s not worth holding out to fulfill a prophecy, but to press on toward final victory. He sums up, “You have proved your valor, my lord. Now, I beseech you, demonstrate your wisdom.”
The Persian points out that the Persians are likely to win here and to overrun all of Greece. What will Greece do without Spartan leadership? He argues that the Spartans have done enough and now a wise retreat is necessary. At the time, it isn’t clear whether Leonidas heeds this or not.