Kingdom of Serbia during World War 1

The Serbian Campaign is the series of campaigns launched against Serbia at the beginning of the First World War.

The first campaign began after Austria Hungary declared war on Serbia on 28 July 1914, the campaign to “punish” Serbia, under the command of Austrian Oskar Potiorek, ended after three unsuccessful Austro-Hungarian invasion attempts were repelled by the Serbs and their Montenegrin allies.

Serbia’s defeat of the Austro-Hungarian invasion of 1914 ranks as one of the great upsets of modern military history.

The Second Campaign was launched, under German command, almost a year later, on 6 October 1915, when Bulgarian, Austrian, and German forces, lead by Field Marshall August von Mackensen, invaded Serbia from three sides, pre-empting the Allied advance from Salonica to help her.

This resulted in the Great Retreat through Montenegro and Albania, the evacuation to Greece, and the establishment of the Macedonian front.

The defeat of Serbia gave the Central Powers temporary mastery over the Balkans, opening up a land route from Berlin to Istanbul, allowing the Germans to re-supply the Ottoman Empire for the rest of the war.

Mackensen declared an end to the campaign on November 24, 1915. Serbia was then divided and occupied by the Habsburg Empire and Bulgaria.

After the Allies launched the Vardar offensive in September 1918, which broke through the Macedonian front and defeated the Bulgarians and their German allies, a Franco-Serbian force advanced into the occupied territories and liberated Serbia, Albania, and Montenegro.
Serbian forces entered Belgrade on 1 November 1918.

The Serbian Army declined severely from about 420,000at its peak to about 100,000 at the moment of liberation.

The estimates of casualties are various: the Serb sources claim that the Kingdom of Serbia lost more than 1,200,000 inhabitants during the war (both army and civilian losses), which represented over 29% of its overall population and 60% of its male population, while western historians put the number either at 45,000 military deaths and 650,000 civilian deaths or 127,355 military deaths and 82,000 civilian deaths.

According to estimates prepared by the Yugoslav government in 1924, Serbia lost 265,164 soldiers or 25% of all mobilized people. By comparison, France lost 16.8%, Germany 15.4%, Russia 11.5%, and Italy 10.3%