WHAT DID THE VATICAN DO TO STOP WORLD WAR ONE?

We don't fully know, do we?

Even though no information has emerged concerning the specific nature of the Pope’s diplomatic activity from June 28, 1914 to August 4, 1914, the day on which the British issued an ultimatum that brought about war with Germany, it is clear from what is know that the Pope’s only desire was for the war not to happen at all. Even though he obviously appreciated the service that Austria had given to the Catholic Church against the Protestants to the North and the Schismatics to the East, from the contents of the interview between the Austrian ambassador and the Pope on July 28th, it is clear that he did not at all approve of Austria’s decision to go to war in order to resolve the Serbian problem. In fact, there have been some witnesses who say that the Pope wrote a letter to Emperor Franz Josef, imploring him to avoid a war. But, Cardinal Merry del Val himself said that he had no knowledge of this letter; there is no trace of it in the Austrian or Roman archives.

...There seemed to be no overt hostility to Wilhelm II from St. Pius X. It is known that Wilhelm, from the House of Hohenzollern (whose senior branch is Catholic in religion), was not overtly hostile to the Catholic Church. He was the one who dismissed Otto von Bismark, the “Iron Chancellor” of the anti-Catholic Kulturkampf, he very much enjoyed trips to visit the pope in the Vatican, and was instrumental in allowing the Jesuits back into Germany after Bismark’s rule. The House of Hohenzollern, of course, allowed the Jesuits to exist in Prussia even after they were disbanded in the rest of Europe due to the Hohenzollern’s gratitude for a critical Jesuit intervention in the beginning of the 18th century, which allowed the Dukes of Prussia to receive a royal crown from the Holy Roman Emperor.

[source : Pope Saint Pius X: Prophet of the Great War, Articles by Dr. Peter Chojnowski, http://drchojnowski.blogspot.co.uk/2006/10/pope-saint-pius-x-prophet-of-great-war.html, 31st October 2006]

So from this the Pope said something to the Austrian Ambassador, but maybe he could have done more?

And the Wilhelm/Jesuit link is interesting...