Above is a picture of Prince Xavier of Bourbon-Parma, Queen Elisabeth of the Belgians and Prince Sixtus of Bourbon-Parma. These two Bourbon princes naturally wished to rush to defend France when World War I started but because the French republic is prejudiced against royalty they were not allowed to join up. Instead, they joined the Belgian army and served with distinction. The two Bourbon-Parma princes were brothers to the Empress Zita of Austria and so when her husband, Charles I, became Emperor of Austria and wanted to end the Great War peacefully it was only natural that they try to do so via Prince Sixtus and Prince Xavier who were officers in the Belgian army, led by King Albert I, who also wanted peace in Europe rather than fighting on to destroy the continent until one side had total victory and the other side total ruin. This is significant since King Albert had greater cause for anger and resentment than any other Allied leader, his country being the only truly innocent party involved. However, King Albert was very religious and Pope Benedict XV wanted a peace without victors and the only leaders who paid attention to him were King Albert and Emperor Charles of Austria.
It was the Austrian emperor who made the first move and later, very secretly, Princes Sixtus and Xavier arrived with the primary French demands for peace, namely the return of Alsace-Lorraine to France, the restoration of Belgium and Serbia and the hand-over of Constantinople to the Russians. Emperor Charles agreed to all of these demands and tried to get the Germans to do the same (though being careful not to let them know what he had done). However, the Germans refused to give up Alsace-Lorraine even when Charles offered to give up some of his own territory to compensate them. They saw victory within sight against Russia and thought that once that was done they could mass all their forces on the western front and crush the Allies in a massive offensive. The French also backed out as they and the British had made secret promises to other powers for Austrian and Hungarian territory. When the Austrians denounced the French for opposing peace they made the letters of Emperor Charles delivered to Paris by Prince Sixtus public. This effectively made Austria the hostage of Germany and ensured the war would continue until the Europe that existed before the war was destroyed forever.