After this they made a second expedition, managed in a similar manner, and this time they pledged their word to Hannibal
and received in return his pledge that he would set Tarentum free and that the Carthaginians would neither exact any kind of tribute from the Tarentines nor impose any other burdens on them; but they were to be allowed, after capturing the city, to plunder the houses and residences of the Romans.
They also agreed on a watchword by which the sentries were to admit them to the camp without any hesitation each time they came.
They thus were enabled to meet Hannibal more than once, sometimes pretending to be going out of the town on a foray, sometimes again on a hunting-party.
Having made their arrangements to serve their purpose in the future, the majority of them awaited the time for action,
the part of huntsman being assigned to Philemenus, as owing to his excessive passion for the chase it was generally thought that he considered it the most important thing in life.
He was therefore directed to ingratiate himself by presents of the game he killed first of all with Gaius Livius the commandant of the town, and then with the guards of the towers behind the Temenid gate. Having been entrusted with this matter, he managed, either by catching game himself or by getting it provided by Hannibal, to keep constantly bringing some in, giving part of it to Gaius and some to the men of the tower to make them always ready to open the postern to him;
for he usually went out and came in by night, on the pretence that he was afraid of the enemy, but as a fact to lay the way for the contemplated attempt.
When Philemenus had once got the guard at the gate into the habit of not making any trouble about it but of opening the postern gate to him at once by night, whenever he whistled on approaching the wall,
the conspirators having learnt that on a certain day the Roman commandant of the place was going to be present at a large and early party in the building called the Museum near the market-place, agreed with Hannibal to make the attempt on that day.
Walbank Commentary