Austrians cross the Drina and begin the first invasion of Serbia

Contemporary chronicles of the war record under 13 August 1914 the crossing of the river Drina by Austro-Hungarian troops and the beginning of the first invasion of Serbia. According to most modern sources, the Austro-Hungarian Fifth Army began crossing on the morning of 12 August, at the same time as the forcing of the Sava near Šabac.

Attack from the west

The Drina separated Serbia from Austro-Hungarian Bosnia. The main part of the invasion force of General Oskar Potiorek struck across this river. The troops crossed at several points, among them near the town of Loznica and the village of Lešnica. The aim was to push deep into the country, into the valley of the river Jadar, and destroy the Serbian army.

The terrain, however, favoured the defenders. Western Serbia was a land of hills, forests and narrow valleys, with few good roads. The Austro-Hungarian columns advanced slowly, in heat and difficult conditions, and their supplies struggled to keep up with the troops.

Putnik’s response

The Serbian commander-in-chief, Vojvoda Radomir Putnik, whom the outbreak of war had caught taking a cure in Austria-Hungary, managed to return home and take command. For the first days of the invasion he waited to establish where the Austrians were striking hardest. When it became clear that the main attack was coming from the west, he sent his troops there. The Serbs took advantage of the fact that the Austro-Hungarian columns were dispersed and did not support one another.

Cer

During the night of 15–16 August, on the slopes of Mount Cer, a battle began that decided the fate of the first invasion. After several days of fierce fighting the Serbs routed the attacking forces. By 24 August the Austro-Hungarian troops had withdrawn behind the Drina and the Sava. It was the first Allied victory of the First World War and a great defeat for Austria-Hungary, which had meant to punish Serbia within a few days. Potiorek renewed the invasion in September and November 1914, but these attempts also ended in defeat.