On 27 July 1914, Leopold Count Berchtold (pictured), the Austro-Hungarian Minister of Foreign Affairs, sent a telegram to Laszlo Count Szogyeny, the Austro-Hungarian Ambassador to Germany, in reply to the Ambassador’s telegrams from 25 July. In his telegram, Berchtold tells Szogyeny to inform the German government of the imminent declaration of war against Serbia.
Count Berchtold to Count Szogyeny. Vienna, 27 July 1914.
Received your Excellency’s telegram of 25 July.
Declaration of war within a few days.
Beginning of war operations must, however, be delayed until the marching up of troops has been completed, so that a decisive blow can be dealt with full force. A certain time will be necessary for this, because experience has taught us not to hurry on military measures on a large scale, before we are certain that there will really be war.
Your Excellency will inform [the German Minister of Foreign Affairs] Herr von Jagow accordingly, begging for strict privacy at the same time.
Source: 1919 Austro-Hungarian Red Book, with minor edits.