According to Prouteau in Gilles de Rais ou la gueule du loup, Gilles was an alcoholic who drank five litres of hippocras per day. This was wine fortified with spices and herbs and, at 20% by volume, twice the strength of ordinary wine. When he was imprisoned, his supply of alcohol was cut off and he was given nothing but water to drink, thus precipitating him into an attack of delirium tremens and rendering him highly susceptible to suggestion. It also meant that the court had in its gift the two things that Gilles could not live without: alcohol and the consolation of the Church. As soon as he admitted to the offences he had been charged with, he would be given hippocras and his excommunication would be revoked.
This is a seductive theory; if Gilles was an addict deprived of his drug, he would have admitted to anything to have it restored to him. As William S Burroughs described the Algebra of Need: "In the words of total need: 'Wouldn't you?' Yes you would. You would lie, cheat, inform on your friends, steal, do anything to satisfy total need. Because you would be in a state of total sickness, total possession, and not in a position to act in any other way." Also, a man in the throes of the DTs and hallucinating would be easy to convince that he had, in fact, done the most outrageous things. However, one has to treat it with caution. Apart from the script that Gilles was made to read about the excesses of his life and the exaggerations of the Mémoire des Héritiers, both highly suspect documents, there is no real indication that Gilles was dependent on alcohol. He may have been a fairly heavy drinker who suffered from forced abstinence in prison, but there is no proof that his gaolers deliberately withheld wine from him in order to break his will, although they certainly would have done if they had thought it would help to brainwash him.
This theory has to be regarded as unproven, but it is hardly needed to explain why Gilles de Rais, after refusing for so long to submit to the will of the court, underwent a complete change of character overnight. He had seen the evidence against him. He knew that it had been extracted by torture and that, subjected to the same torture, he would inevitably break and recite the same litany of atrocities. He knew that he would be condemned and executed. He believed that if he went to his death contumacious and excommunicate, he would be plunged into Hell forever. And so he took the only option that would minimise his pain both in this world and the next; he ate humble pie and read the confession that had been prepared for him and that is so clearly based on the forced testimony of Henriet and Poitou, even though that would inevitably lead to shame and death, because shame and death were infinitely preferable to torment on earth that would continue for eternity in Hell.
Illustration from La trilogie Gilles de Rais by Jacques Martin/Jean Pleyer.
(Interestingly, although it is not too difficult to find images of Gilles feasting, representations of him drinking are vanishingly rare.).