On June 28, 1914, Gavrilo Princip assassinated Archduke Franz Ferdinand of Austria and his wife, Duchess Sophie, in Sarajevo.
A month later, on July 28, Austria-Hungary declared war on Serbia, and on August 1, Germany declared war on Russia.
On August 2, Germany invaded Luxembourg, and the skirmish at Joncherey in France—the first military action on the Western Front—took place. That same day, Pope St. Pius X issued a Latin-language exhortation to all the Catholics of the world to pray for peace. What follows is a translation of the pope’s words, which were published in Acta Apostolicae Sedis (vol. VI, no. 11, p. 373).
Acta Apostolicae Sedis records no subsequent texts of Pius X, who fell ill on August 15. He took a sharp turn for the worse on August 19, and died at 1:15 AM on August 20.
TO ALL THE CATHOLICS OF THE WORLD
While nearly all Europe is being driven into the tortuous ways of most destructive war—he who has reflected a little upon what dangers, what massacres, what result there would be would assuredly perceive himself overwhelmed with sorrow and trembling—We Ourselves also cannot but be most grievously affected, cannot but be tormented with a most bitter mourning in spirit, because we are solicitous for the salvation and also the life of so many citizens, of so many peoples. In so great a disturbance of all affairs, and at a critical moment, We clearly perceive and understand that paternal charity demands this from Us, that the apostolic ministry demands this: that We more vehemently direct the spirits of all Christ’s faithful to that place whence help comes, to Christ, We say, the prince of peace and most powerful mediator of God and men. We therefore exhort that all approach the throne of grace and of mercy, as many Catholics as there are throughout the world, and in the first place men from the clergy; whose duty, moreover, it will be, at the command of bishops, to carry out public supplications in every single parish, that the merciful God, exhausted as it were by the prayers of the pious, may take away the destructive flames of war—the sooner the better—and that, beneficent, He may grant to those who preside over civil affairs to think thoughts of peace and not of affliction.
From the Vatican, on the second day of August 1914.
POPE PIUS X