The first efforts to prosecute war crimes were made after World War I. The Treaty of Versailles demanded the extradition of the German Kaiser, who was to be put on "public trial." Another 890 German civilian and military officials were supposed to face Allied tribunals.
However, the German side prevailed in its demand for the trials against German war criminals to be held before the Leipzig Reich Court, for the first time under international law. Nonetheless, few of the trials conducted were deemed to be serious, and the sentences were very mild.
The experience with the failed Leipzig Trials strengthened the Allies' resolve in 1945 to prosecute the Nazi war crimes themselves.