After a night’s sleep (though one wonders how sound such sleep was) the Serbians reconvened on the morning of Sunday, July 25, 1914 and agreed to heed the advice from London and Paris and accede to all ten Austria-Hungarian demands with only slight reservations. There would be no war.
Then, shortly after noon, word arrived from the Serbian ambassador at the Tsar’s country palace that the Russians were eager to defy Austria-Hungary’s show of power. While not yet ready to proceed to full mobilization, the Tsar had announced a preliminary “Period Preparatory to War” at 11:00 a.m.
Quickly a reply was drafted and edited, and then re-drafted and re-edited, with time running down: Serbia attached conditions to six of the Austria-Hungarian demands and flatly rejected any participation by Austria-Hungary in the Serbian investigation of Archduke Franz Ferdinand’s assassination.
With fifteen minutes to go, the Serbian Prime Minister himself delivered the document to the Austrian ambassador. The Austrian embassy personnel boarded a train and left Belgrade for Austria within the hour.
Now it was up to Austria-Hungary. It had not delivered an ultimatum but a note, so, diplomatically speaking, it had left the door open not to declare war on Serbia should the terms of the note not be accepted. Now the question was, would Austria-Hungary use that door to avoid war?
Two tense days followed. Serbia mobilized its small army. Russia recalled reservists to the western military zones. The Germans signaled that further Russian action would lead to German mobilization (which “would mean war” according to the German ambassador in St. Petersburg).
The British and French attempted to restrain further Russian action. They notified Germany there was a likelihood Russia may soften its position.
On Monday, July 26, the Austrians informed the German ambassador war would be declared “tomorrow, at the latest the day after.”
Germany did not signal Austria-Hungary to back down.
From John Keegan’s The First World War.