Austria-Hungary orders partial mobilisation against Serbia

After breaking off diplomatic relations with Serbia, Austria-Hungary moved without delay from words to military preparations. On the evening of 25 July 1914 Emperor Franz Joseph, staying at his summer residence in Bad Ischl, signed the order for partial mobilisation. The next day, 26 July, it was already a fact that every European capital had to reckon with.

The mobilisation did not cover the whole Austro-Hungarian Army. The Chief of the General Staff, Franz Conrad von Hötzendorf, set in motion the so-called Plan B, a war plan intended solely for a fight with Serbia and Montenegro. Only the units that were to fight in the Balkans were called up. The first day of mobilisation was set for 28 July, the day on which the monarchy declared war on Serbia.

Mobilisation was a slow process. Reservists had to be called up, equipped and carried by rail to the frontier. That is why, despite Vienna’s haste, the troops commanded by Oskar Potiorek did not launch their offensive against Serbia until mid-August. The swift punishment of Belgrade that the Austro-Hungarian decision-makers had counted on proved impossible.

The most serious problem, however, lay in the east. Partial mobilisation assumed that Russia would not enter the war. If St Petersburg stood up for Serbia, the forces sent to the Balkans would be needed above all in Galicia, on the border with Russia. Meanwhile, from 26 July Russia was already introducing the so-called period preparatory to war. Conrad’s plan, designed for a local reckoning with Serbia, thus rested from the outset on a very risky assumption.

On 26 July 1914 Austria-Hungary became the first of the great powers to set its military machine in motion. From then on the July Crisis ran according to two clocks: the diplomatic one and the mobilisation one. The latter increasingly dictated the pace of events.