The hatred borne them by their subjects was to Cesare a sufficient guarantee that they would not be likely to attempt a return to their dominions, and so he permitted them to keep their lives.

But to have allowed Astorre Manfredi, or even his bastard brother, to live would have been bad policy from the appallingly egotistical point of view which was Cesare's--a point of view, remember, which receives Macchiavelli's horribly intellectual, utterly unsentimental, revoltingly practical approval.
So--to anticipate a little--we see Cesare taking Astorre and Gianevangelista Manfredi to Rome when he returned thither in the following June.

A fortnight later--on June 26--the formidable amazon of Forli, the Countess Sforza-Riario, was liberated, as we know, from the Castle of Sant' Angelo, and permitted to withdraw to Florence.

But the gates of that grim fortress, in opening to allow her to pass out, opened also for the purpose of admitting Astorre and Gianevangelista, upon whom they closed.
All that is known positively of the fate of these unfortunate young men is that they never came forth again alive.
The record in Burchard (June 9, 1502) of Astorre's body having been found in the Tiber with a stone round his neck, suffers in probability from the addition that, "together with it were found the bodies of two young men with their arms tied, a certain woman, and many others." The dispatch of Giustiniani to the effect that: "It is said that this night were thrown into Tiber and drowned the two lords of Faenza together with their seneschal," was never followed up by any other dispatch confirming the rumour, nor is it confirmed by any dispatch so far discovered from any other ambassador, nor yet does the matter find place in the Chronicles of Faenza.
But that is of secondary importance.

The ugliest feature of the case is not the actual assassination of the young men, but the fact that Cesare had pledged himself that Astorre should go free, and yet had kept him by him--at first, it would seem, in his train, and later as a prisoner--until he put an end to his life.