On 27 July 1914, Laszlo Count Szogyeny, the Austro-Hungarian Ambassador to Germany (pictured), sent a coded private telegram to Leopold Count Berchtold, the Austro-Hungarian Minister of Foreign Affairs. In his telegram, Szogyeny discusses Austro-Hungarian mobilisation.
Count Szogyeny to Count Berchtold. Berlin, 27 July 1914.
Cyphered.— Strictly private.
[The German] Minister of Foreign Affairs tells me that [the German Ambassador to Austria-Hungary] Herr von Tschirschky telegraphs:
[Austro-Hungary Chief of Staff] General Conrad von Hötzendorf informed him privately that, to be effective against Servia from a military point of view, our mobilisation could not be accomplished before 12 August 1914.
At the same time, the Minister of Foreign Affairs said that he regretted that the term of the beginning of our military action should have to be postponed so far.
Source: 1919 Austro-Hungarian Red Book, with minor edits.