The campaign, euphemistically dubbed "punitive expedition" (German: Strafexpedition) by the Austro-Hungarian leadership,[3] was under the command of Austrian General Oskar Potiorek.

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

[11][12] More recent historical analysis has estimated that roughly 177,000 Serbian soldiers lost their lives or were not returned from captivity, while the civilian death toll is impossible to determine, numbering in the hundreds of thousands.

The resulting Treaty of London further shrank the Ottoman Empire by creating an independent Principality of Albania and enlarging the territorial holdings of Bulgaria, Serbia, Montenegro, and Greece.

Though Serbia had an experienced army, it was exhausted from the conflicts of the Balkan Wars and poorly equipped, which led the Austro-Hungarians to believe it would fall in less than a month.

][better source needed] According to the official Austrian documents in the period from September until the end of December 1914, some 160,000 replacement troops were sent to the Balkan theatre of war, as well as 82,000 reinforcements as part of newly formed units.

Eventually, the AOK allowed General Oskar Potiorek to deploy a significant segment of the 2nd army (around four divisions) in fighting against Serbia, which caused a delay in the transport of these troops to the Russian front for more than a week.

In addition, most of the soldiers — ethnic Czechs, Slovaks, Poles, Romanians and South Slavs — had linguistic and cultural links with the empire's various enemies.

This shortage of military power forced the Serbian army to recruit under and over-aged men to make up for losses in the opening phase of the war.

[27] The Serbian troops did not have service issued boots at all, and the vast majority of them wore everyday footwear made of pig skin called opanak.

Because Serbia lacked a significant domestic military-industrial complex, its army depended entirely on imports of ammunition and arms from France and Russia, which were chronically short of supplies.

These figures detail the number of all Austro-Hungarian troops concentrated on the southern (Serbian) theatre of war at the beginning of August 1914 and the resources of the entire Serbian army (however, the number of troops available for the operations on both sides was somewhat less): Serbia's ally Montenegro mustered an army of about 45–50,000 men, with only 14 modern quick-firing field guns, 62 machine guns and some 51 older pieces (some of them antique models from the 1870s).

French and Serbian forces re-took limited areas of Macedonia by recapturing Bitola on 19 November 1916 as a result of the costly Monastir Offensive, which brought stabilization of the front.

[29] Hindenburg and Ludendorff concluded that the strategic and operational balance had now shifted decidedly against the Central Powers and insisted on an immediate peace settlement during a meeting with government officials a day after the Bulgarian collapse.

[30] On 29 September 1918, the German Supreme Army Command informed Kaiser Wilhelm II and the Imperial Chancellor Count Georg von Hertling, that the military situation facing Germany was hopeless .

[32][33] The collapse of the Macedonian front meant that the road to Budapest and Vienna was now opened for the 670,000-strong Army of General Franchet d'Esperey as the Bulgarian surrender deprived the Central Powers of the 278 infantry battalions and 1,500 guns (the equivalent of some 25 to 30 German divisions) that were previously holding the line.

[34] In September, Entente armies spearheaded by Serbian and French troops, broke through the remaining German and Bulgarians defense, forcing Bulgaria to exit the war and liberating Serbia two weeks before the ceasefire.

When World War I ended, the Treaty of Neuilly awarded Western Thrace to Greece, whereas Serbia received some minor territorial concessions from Bulgaria.

[37] The number of civilian deaths is estimated by some sources at 650,000, primarily due to the typhus outbreak and famine, but also direct clashes with the occupiers.

[39] According to the Serb sources, the total number of casualties is placed around 1,000,000:[40] 25% of Serbia's prewar size, and an absolute majority (57%) of its overall male population.

The extent of the Serbian demographic disaster can be illustrated by the statement of the Bulgarian Prime Minister Vasil Radoslavov: "Serbia ceased to exist" (New York Times, summer 1917).

[50] The assassination in Sarajevo of Archduke Franz Ferdinand of Austria and his wife Sophie, Duchess of Hohenberg was followed by violent anti-Serb demonstrations of angry Croats and Muslims[51] in the city during the evening of 28 June 1914 and for much of the following day.

This happened because most Croats and many Muslims considered the archduke the best hope for establishing a South Slav political entity within the Habsburg Empire.

[53][54] Incited by anti-Serbian propaganda and collusion with the command of the Austro-Hungarian Army, soldiers committed numerous atrocities against the Serbs in both Serbia and Austria-Hungary.

Fruit trees were cut down, and water wells were poisoned in an effort on the Austro-Hungarian part to discourage Serb inhabitants from ever returning.