Simultaneous interpretation was invented for the Nuremberg trials

Before 1945, courtroom interpreting happened one sentence at a time, roughly doubling a trial's length. Léon Dostert adapted an IBM headset-and-microphone system so English, French, German and Russian could all be interpreted live, at once, for the Nazi war crimes trials. The method worked so well it became the standard the UN and every major international body still uses.

— The National WWII Museum, Translating and Interpreting the Nuremberg Trials — nationalww2museum.org article