Anybody who has read about Gilles de Rais in a biography or on a website and later gone on to read the trial records will have wondered why the latter seem so pallid in comparison. The small details that so enliven other accounts are simply absent. In particular, anybody who has read The Bloody Countess by Valentine Penrose, with its counterpointed story of Gilles de Rais, will have marvelled at the first person quotes and the colourful anecdotes and descriptions.
The reason is that Penrose and other biographers leaned heavily upon a "more circumstantial" record of the trial, penned by Paul Lacroix, The Bibliophile Jacob, in the mid-nineteenth century. It is a very strange document, entirely bogus. M. Lacroix claimed to have had access to a far more detailed copy of the record than the one kept in the archive at Nantes. Instead of being written in a distancing third person, he uses first person speech throughout. Henriet and Poitou come out best in this account, they are clearly distinguished as personalities and their motives for confessing are explained. These do not include torture, the Bibliophile is far from a revisionist. On the down side, we do lose Prelati's testimony as he has unfortunately died before coming to trial. There is a prototype for the veiling of the cross, but it is done by Pierre de l'Hôpital before Henriet gives his evidence; J-K Huymans much improved upon and dramatised the scene.
It is, in short, a piece of fantasy loosely based on Gilles' trial. But it is highly entertaining and of interest, so a link to the full text is given here. Only in French, unfortunately, but not difficult to decipher if you have a little French from school days. If not, you can get the flavour of it from Penrose's book (which deals mainly with Elisabeth Bathory) or from the extracts from that book in Dark Star: the Satanic Rites of Gilles de Rais, edited by Candice Black.
And is the Bibliophile Jacob's work of fiction relevant to our theme? Yes, because it is so obviously and consistently in error throughout that anybody reading it in parallel with a genuine account of the trial would immediately realise that it is unreliable. Yet several reputable biographers, including Bossard, borrow from it to add a bit of colour to their story; and that is how Gilles de Rais has come to be surrounded by myths and untruths, and why a truly authoritative biography does not exist.