He enlivened it by every scrap of scandalous gossip that reached him, however alien to his avowed task.

The authenticity of this scandalmongering chronicle has been questioned; but, even assuming it to be authentic, it is so wildly inaccurate when dealing with matters happening beyond the walls of Perugia as to be utterly worthless.
Matarazzo relates the story of the incestuous relations prevailing in the Borgia family, and with an unsparing wealth of detail not to be found elsewhere; but on the subject of the murder he has a tale to tell entirely different from any other that has been left us.

For, whilst he urges the incest as the motive of the crime, the murderer, he tells us, was Giovanni Sforza, the outraged husband; and he gives us the fullest details of that murder, time and place and exactly how committed, and all the other matters which have never been brought to light.
It is all a worthless, garbled piece of fiction, most obviously; as such it has ever been treated; but it is as plausible as it is untrue, and, at least, as authoritative as any available evidence assigning the guilt to Cesare.
SANUTO we accept as a more or less careful and painstaking chronicler, whose writings are valuable; and Sanuto on the matter of the murder confines himself to quoting the letter of February 1498, in which the accusation against Cesare is first mentioned, after having given other earlier letters which accuse first Ascanio and then Orsini far more positively than does the latter letter accuse Cesare.
On the matter of the incest there is no word in Sanuto; but there is mention of Dona Sancia's indiscretions, and the suggestion that, through jealousy on her account, it was rumoured that the murder had been committed--another proof of how vague and ill-defined the rumours were.
PIETRO MARTIRE D'ANGHIERA writes from Burgos, in Spain, that he is convinced of the fratricide.

It is interesting to know of that conviction of his; but difficult to conceive how it is to be accepted as evidence.
If more needs to be said of him, let it be mentioned that the letter in which he expresses that conviction is dated April 1497--two months before the murder took place! So that even Gregorovius is forced to doubt the authenticity of that document.
GUICCIARDINI is not a contemporary chronicler of events as they happened, but an historian writing some thirty years later.

He merely repeats what Capello and others have said before him.