At the Nuremberg trials the holocaust was one of the indictments. None of the defendants pretended that the holocaust had not happened, because this was not credible, and they didn't want to concede that the holocaust was wrong.
However, I wonder if I might have mistaken their reasons for not pursuing holocaust denial as a legal argument.
I read the Charter of the International Military Tribunal, the foundational text for the Nuremberg trial. In Article 21, it says
The Tribunal shall not require proof of facts of common knowledge but shall take judicial notice thereof. It shall also take judicial notice of official governmental documents and reports of the United Nations, including the acts and documents of the committees set up in the various allied countries for the investigation of war crimes, and of records and findings of military or other Tribunals of any of the United Nations.
So, does this mean that the defendants were not allowed to question that millions of people were killed in the holocaust? Was this one of the 'facts of common knowledge'?