Final answer:
The German officials tried at the Nuremberg Trials violated the Nuremberg Principles, which include crimes against peace, war crimes, and crimes against humanity. These principles were foundational in the creation of international criminal law and were not solely based on the Geneva Conventions.
Step-by-step explanation:
The officials from Germany's Third Reich who were prosecuted after World War II in the international tribunal at Nuremberg were primarily charged with violating what came to be known as the Nuremberg Principles. These principles were a set of guidelines for determining what constitutes a war crime, and they include crimes against peace, war crimes, and crimes against humanity. The Nuremberg Principles paved the way for the development of international criminal law, and they also helped define concepts like genocide and the broader body of international human rights law that followed.
The tribunal did not exclusively rely on the existing Geneva Conventions, which at that time mostly dealt with the treatment of wounded soldiers, maritime warfare, and the rights of prisoners of war. However, the conventions were part of the broader context of humanitarian law that influenced the Nuremberg Trials. While challenging the defense of just "following orders," the tribunal established that individuals could be held accountable for their actions, even during war, an important principle in both international and humanitarian law.