femmenietzsche:

Here’s an interesting study in how two sources report the same event. First, Xenophon on the run-up to the Battle of Leuctra, in which Thebes won a shocking victory against Sparta that destroyed Spartan hegemony over Greece. According to him, all the omens for Thebes were hopeful, although he notes with skepticism the claim that the omens were faked:

The leaders on the Theban side believed that if they did not fight it out with Kleombrotos, the cities that were their neighbors would revolt and their own city would be besieged. They also believed that if their city came under siege and failed to obtain necessary provisions, the citizens would probably turn against them; and since many of them had already been in exile before, they felt it would be better to fight it out now and die rather than to go into exile again. [7] Aside from these considerations, they were encouraged in their resolve by an oracle that had said the Spartans would be defeated near the monument to the virgins. (These virgins were said to have killed themselves because they had been violated by some Spartans.) The Thebans decorated this monument before the battle. Then again, they were receiving reports from the city that the doors of the temples there had opened up of their own accord, and that the priestesses were claiming that the gods were doing this as a sign of victory; and it was also said that  the arms of Herakles had vanished from his temple, the reason being put forth that he had gone out for the battle to come. Now there are some who claim that all these portents were contrived by the men in control of the city. [8] Whatever was the case, in the battle itself everything went against the Spartans, while for their opponents everything went right, even what happened by chance.

Now here’s the historian Diodorus Siculus reporting the same thing, except that according to him the omens were all bad, and Thebes’ non-superstitious commander Epaminondas had to fake a bunch of positive omens to reassure his jittery troops:

Epaminondas called up for active service all Thebans of military age, enlisted the best trained of the other Boeotians, and marched from Thebes at the head of a force that numbered no more than six thousand all told. [3] During the troops’ exodus from the city, many of them observed what they took to be unfavorable omens for the expedition. At the city gates Epaminondas and his men encountered a town crier, giving notice in the prescribed fashion of a runaway blind slave and warning people not to hide him or smuggle him out of Thebes but, rather, to lay hands on him and bring him back. [4] The older men among those who heard this town crier regarded his words as an omen for the future, whereas the younger ones kept quiet, in case they should be thought to be dissuading Epaminondas from the campaign out of cowardice. 

To those telling him he should pay heed to such omens Epaminondas replied: “One omen is best, to fight to defend your country.” [5] This forthright response by Epaminondas took the pious aback. But then a second omen appeared, more unfavorable than the first. When the staff orderly came forward, holding a spear with a ribbon attached to it, and began to announce the orders from headquarters, a gust of wind detached the ribbon and wrapped it around a gravestone. Now it was here that lay buried certain Lacedaemonians and Peloponnesians who had died while on campaign with Agesilaos. [6] Some of the older men, again, who happened to be present made a solemn protest against the army taking the field when the gods were so obviously opposed to it. Epaminondas made no reply to them but led his army on regardless, convinced that a reasoned decision in favor of what was right and a firm regard for what was just offered a preferable choice to these present signs. [7] At the time, then, Epaminondas–who had been trained in philosophy and made sensible use of the arguments he had absorbed as part of his education–incurred severe criticism from a number of people; but later, as a result of his successes, he was regarded as a man of outstanding military skill, and indeed rendered the greatest services to his country. So he at once led out his forces, occupied the pass at Coronea in advance of the enemy, and set up his camp there. 

…

Epaminondas, noting the superstitious fear affecting his troops on account of the portents that had occurred, deployed all his personal resourcefulness and military guile in a determined effort to counter the nervous piety of the rank and file. A number of men had lately arrived from Thebes, and he persuaded them to say that the arms in the temple of Herakles had mysteriously vanished and that a rumor had  gone around in Thebes that the heroes of ancient times had taken them and departed to help the Boeotians. He also produced another man who had supposedly just come back from a descent to the oracular cave of Trophonios, who claimed that the god instructed them, when they were victorious at Leuctra, to establish a contest in honor of Zeus the king, with garlands as prizes. This is the origin of the festival celebrated by the Boeotians at Lebadeia.

[1] Another contributor to the success of such trickery was the Spartan Leandrias, an exile from Lacedaemon then on active service with the Thebans. He was brought forward in the Assembly and asserted that there was an ancient saying among the Spartans that they would lose their hegemony when they were defeated by the Thebans at Leuctra. [2] Epaminondas was also approached by certain local oracle-mongers, claiming that the Lacedaemonians were fated to suffer a major disaster near the tomb of the daughters of Leuktros and Skedasos. [3] Leuktros was the person from whom the plain derived its name. His daughters, together with those of one Skedasos, had been raped by some Lacedaemonian ambassadors: the victims, unable to endure this outrage, called down curses on the country that had sent out their violators and then took their own lives. [4] Many other such tales were reported. When Epaminondas then called an assembly and in his own words rallied the troops to face the struggle ahead, they all had a change of heart, shook off their superstitious fears, and looked forward to the coming battle in high spirits.