24. Of Passwords
1. In giving the password, if your force includes men of different cities or nationalities, take care not to give a word whose meaning can be equally well expressed by another word, as for instance Dioscuri and Tyndaridae, where the two different words mean the same; 2. or again Ares and Enyalius, Athena and Pallas, sword [xiphos] and cutlass [encheiridion], lamp and light, and similar expressions which are hard to remember because of the different usages in every nation [ethnos], and are a source of danger if a dialect form instead of one generally familiar is issued as the password. 3. Thus when mixed mercenary troops or allies of different nationalities form part of your force, such passwords should be avoided.
I will give as an instance what happened in Aeolis to Charidemus of Oreus, after he had captured the town of Ilion by the following stratagem. 4. The governor of Ilion had a slave who constantly went out to steal, especially at night, when he used to go out and return again each time with the results of the night’s work. 5. After a time Charidemus found this out, made the slave’s acquaintance, and came to a secret understanding whereby he induced him to go out as if to steal on a specified night: he was to go out during the night with a horse, so that the gates might be opened for him on his return, instead of his entering by the passage (or wicket), as he usually did. 6. When he arrived outside, he interviewed Charidemus and chose from his force about thirty mercenaries, armed with breastplates, daggers, shields, and close-fitting helmets. 7. These he led off in the dark, in shabby clothing and with their arms concealed, making them look like prisoners, and brought them into the town along with some women and children, also dressed as prisoners, the gates being opened to let the horse pass through. 8. No sooner had they entered than they set to work, slew the sentinel, behaved as mercenaries usually do, and succeeded in occupying the gates, at which troops at once arrived and seized the citadel; for Charidemus was close at hand. 9. Afterwards Charidemus himself entered with the main body, 10 but took care at the same time to place a detachment in ambush, suspecting that a force would be sent to recapture the city, as was indeed the case. For on hearing the news, Athenodorus of Imbros, who with his army was at no great distance, tried at once to send help. 11. He, too, was a shrewd man and also had his suspicions about an ambush: so he avoided the route to Ilion on which the ambush was placed, took another road in the dark without being seen, and arrived at the city gates. 12. Then some of his men slipped into the city, passing amid the confusion for members of Charidemus’ army. 13. But before any more could enter, they were discovered by means of the password, and some were driven out, others slain at the gates; for the relieving force gave the password as ‘Tyndaridae’, while Charidemus’ password was really ‘Dioscuri’. 14. This, and nothing else, saved Ilion from being at once recaptured by Athenodorus the same night.
The passwords given should therefore be easy to remember, and as nearly related as possible to the business in hand: 15. for instance, for a foray ‘Artemis the Huntress’; for secret exploits ‘Hermes the cunning’; in case of an assault ‘Heracles’; for open attacks ‘Sun’ and ‘Moon’; and so on as far as possible, using words that will be intelligible to all. 16. Iphicrates used even to say that rounds and sentries should not have the same password, but that a different one should be assigned to each: for instance, the man challenged would answer ‘Zeus the Saviour’ (if this happened to be the word), and the reply of the challenger might be ‘Poseidon’. This would minimise the risk of disasters arising from the betrayal of a password to the enemy.
17. In case the guards get separated, arrange in advance for them to communicate by whistling: for this will convey nothing to those who do not know it, whether they are Hellenes or Barbarians. 18. But look after your dogs: otherwise, when they hear the whistle, they may cause trouble. Whistling was used to collect the troops at Thebes during the recapture of the Cadmeia, when they got separated and did not know one another in the dark.
19. Rounds and patrols should both demand the password: it is no use for only one to do so. For an enemy might challenge just as well as a man going the rounds.