Prisoners...

[Hax]

I believe Pyrrhos released all of the Roman prisoners after the Roman general (whose name escapes me) forwarded a letter sent by Pyrrhos' doctor who was plotting to poison him.

Edit: His name was Gaius Fabricius Luscinus. From Wikipedia:

Edit 2: From Wikipedia:

After the Romans were defeated by Pyrrhus at Heraclea, Fabricius negotiated peace terms with Pyrrhus and maybe the ransom and exchange of prisoners; Plutarch (Pyrrhus 18) reports that Pyrrhus was impressed by his inability to bribe Fabricius, and released the prisoners even without a ransom.

I just looked it up for you:

Spoiler Alert, click show to read: 

Then Caius Fabricius came in embassy from the Romans to treat about the prisoners that were taken, one whom Cineas had reported to be a man of highest consideration among them as an honest man and a good soldier, but extremely poor. Pyrrhus received him with much kindness, and privately would have persuaded him to accept of his gold, not for any evil purpose, but calling it a mark of respect and hospitable kindness. Upon Fabricius's refusal, he pressed him no further, but the next day, having a mind to discompose him, as he had never seen an elephant before, he commanded one of the largest, completely armed, to be placed behind the hangings, as they were talking together. Which being done, upon a sign given, the hanging was drawn aside, and the elephant, raising his trunk over the head of Fabricius, made an horrid and ugly noise. He, gently turning about and smiling, said to Pyrrhus, "Neither your money yesterday, nor this beast to-day, makes any impression upon me." At supper, amongst all sorts of things that were discoursed of, but more particularly Greece and the philosophers there, Cineas, by accident, had occasion to speak of Epicurus, and explained the opinions his followers hold about the gods and the commonwealth, and the objects of life, placing the chief happiness of man in pleasure, and declining public affairs as an injury and disturbance of a happy life, removing the gods afar off both from kindness or anger, or any concern for us at all, to a life wholly without business and flowing in pleasures. Before he had done speaking, "O Hercules!" Fabricius cried out to Pyrrhus, "may Pyrrhus and the Samnites entertain themselves with this sort of opinions as long as they are in war with us."

Pyrrhus, admiring the wisdom and gravity of the man, was the more transported with desire of making friendship instead of war with the city, and entreated him, personally, after the peace should be concluded, to accept of living with him as the chief of his ministers and generals. Fabricius answered quietly, "Sir, this will not be for your advantage, for they who now honour and admire you, when they have had experience of me, will rather choose to be governed by me than by you." Such was Fabricius. And Pyrrhus received his answer without any resentment or tyrannic passion; nay, among his friends he highly commended the great mind of Fabricius, and intrusted the prisoners to him alone, on condition that if the senate should not vote a peace, after they had conversed with their friends and celebrated the festival of Saturn, they should be remanded. And, accordingly, they were sent back after the holidays; it being decreed pain of death for any that stayed behind.