28. On Gate Keeping
1. The following precautions, too, should be taken in a city which is afraid of attack.
All gates should be kept shut except one, which should be in the part of the city most difficult to access, and so situated that anyone approaching it will be visible a long way off. 2. Even here only the wicket gate should remain open, so that men have to pass in or out one by one: in this way anyone seeking to desert or a spy seeking to gain entrance will have little chance of escaping detection – that is if the sentry at the gate has his wits about him. 3. To open the whole gate for beasts of burden, carts, and merchandise is dangerous. If it is necessary to bring in without delay corn, oil, wine or similar articles in carts or with a number of carriers, they must be taken in at the nearest gate ‹under the escort of a troop sent out to meet them›: this will be the quickest and easiest way. 4. As a rule, gates should not be opened incautiously early in the day, but only later on, and no-one should be allowed to leave the city until the immediate neighbourhood has been thoroughly explored. Again, boats must not come to anchor in front of the gates, but lie further off, since even in the daytime the opening of both gates has been the occasion for many successful attempts, aided by stratagems or pretexts which I will now illustrate; for many similar ruses have been employed for this same object.
5. Python of Clazomenae, who had accomplices in the city, waited carefully for the quietest time of day, at which he had arranged for carts to bring in a load of wine-casks [pithoi], and then seized Clazomenae while the carts were standing in the gateway this enabled a force of mercenaries, waiting in concealment close at hand, to make their way in and capture the city, some pf the citizens not knowing what was going on, and some being too late to prevent it, while others were accomplices in the plot.
6. Again, Iphiades of Abydos was trying to take Parion on the Hellespont. Besides making secret preparations for scaling the wall by night, he filed carts with faggots and brambles, and sent them up to the wall after the gates had been shut, as if they belonged to the town. They actually came right up to the gates and bivouacked there, pretending to be afraid of the enemy. 7. The arrangement was there, pretending that the carts were to be set alight at a certain time so that the gates might catch fire; then, while the citizens were all intent on putting out the fire, Iphiades himself was to enter at another point.
I have thought it best to collect these precepts to show the several precautions which should be taken at the various times, that no-one may be too ready to accept anything without due examination.