It was an ugly, unscrupulous deed; but there is no need to exaggerate its heinousness, as is constantly done, upon no better authority than Guicciardini's, who wrote that the murder had been committed "saziata prima la libidine di qualcuno." Of all the unspeakable calumnies of which the Borgias have been the subject, none is more utterly wanton than this foul exhalation of Guicciardini's lewd invention.

Let the shame that must eternally attach to him for it brand also those subsequent writers who repeated and retailed that abominable and utterly unsupported accusation, and more particularly those who have not hesitated to assume that Guicciardini's "qualcuno" was an old man in his seventy-second year--Pope Alexander VI.
Others a little more merciful, a little more careful of physical possibilities (but no whit less salacious) have taken it that Cesare was intended by the Florentine historian.
But, under one form or another, the lie has spread as only such foulness can spread.

It has become woven into the warp of history; it has grown to be one of those "facts" which are unquestioningly accepted, but it stands upon no better foundation than the frequent repetition which a charge so monstrous could not escape.

Its source is not a contemporary one.

It is first mentioned by Guicciardini; and there is no logical conclusion to be formed other than that Guicciardini invented it.
Another story which owes its existence mainly, and its particulars almost entirely, to Guicciardini's libellous pen--the story of the death of Alexander VI, which in its place shall be examined--provoked the righteous anger of Voltaire.