The Battle of Kolubara (Serbian Cyrillic: Колубарска битка, German: Schlacht an der Kolubara) was fought between Austria-Hungary and Serbia in November and December 1914, during the Serbian Campaign of 1914.
It commenced on 16 November, when the Austro-Hungarians under the command of Oskar Potiorek reached the Kolubara river during their third invasion of Serbia that year, having captured the strategic town of Valjevo and forced the Serbian army to undertake a series of retreats. The Serbs withdrew from Belgrade on 29–30 November, and the city soon fell under Austro-Hungarian control.
On 2 December, the Serbian army launched a surprise counterattack all along the front. Valjevo and Užice were retaken by the Serbs on 8 December. The Austro-Hungarians retreated to Belgrade, which 5th Army commander Liborius Ritter von Frank deemed untenable. The Austro-Hungarians abandoned the city between 14 and 15 December and retreated into Austria-Hungary, allowing the Serbs to retake their capital the following day.
The Austro-Hungarians and the Serbs suffered heavy casualties, with more than 20,000 dead on each side. The defeat humiliated Austria-Hungary, which had hoped to occupy Serbia by the end of 1914. On 22 December, Potiorek and von Frank were relieved of their respective commands, and the 5th and 6th Armies were merged into a single 5th Army of 95,000 men.
Background
On 28 June 1914, the Bosnian Serb student Gavrilo Princip assassinated Archduke Franz Ferdinand of Austria in Sarajevo. The assassination precipitated the July Crisis, which led Austria-Hungary to issue an ultimatum to Serbia on 23 July because it suspected that the assassination had been planned in Belgrade. The Austro-Hungarian ultimatum was designed to be unacceptable to Serbia and was indeed rejected. The Austro-Hungarians declared war on Serbia on 28 July. The same day, the Serbs destroyed all bridges on the Sava and Danube rivers to prevent the Austro-Hungarians from using them during any future invasion. Belgrade was shelled the following day, which marked the beginning of World War I.
Fighting in Eastern Europe began with the first Austro-Hungarian invasion of Serbia in early August 1914, under the command of Oskar Potiorek. The number of Austro-Hungarian troops assigned to the invasion was far smaller than the force of 308,000 that had been intended when war was declared since much of the Austro-Hungarian 2nd Army had moved to the Russian front. That reduced the number of troops involved in the initial stages of the invasion to approximately 200,000. On the other hand, the Serbs could muster some 450,000 men to oppose the Austro-Hungarians upon full mobilization. The main elements to face the Austro-Hungarians were the 1st, 2nd, 3rd and Užice Armies, with a combined strength of approximately 180,000 men. The Serbian Army was commanded by Crown Prince Alexander, with the chief of the Serbian general staff, Radomir Putnik, as his deputy and de facto military leader. Petar Bojović, Stepa Stepanović, Pavle Jurišić Šturm and Miloš Božanović commanded the 1st, 2nd, 3rd and Užice Armies, respectively.
The Balkan Wars had only just concluded, and Serbia was still recovering. Over 36,000 Serbian soldiers had been killed and 55,000 seriously wounded. Few recruits had been gained from the newly acquired territories, and the Serbian army had been stretched by the need to garrison them against Albanian insurgents and the threat of a Bulgarian attack. To compound matters, the Serbs were dangerously short of artillery and had only begun replenishing their ammunition stocks. Their supply problems also extended to more basic items. Many soldiers lacked any uniform other than a standard issue greatcoat and a traditional Serbian cap known as a šajkača. Rifles were also in critically short supply. It was estimated that fully mobilizing would leave about 50,000 Serbian soldiers lacking equipment. The Austro-Hungarians, on the other hand, had an abundance of modern rifles, twice as many machine guns and field guns as the Serbs also had better stocks of munitions and much better transport and industrial infrastructure behind them. The Serbs had a slight advantage over the Austro-Hungarians, as many of their soldiers were experienced veterans of the Balkan Wars and were better trained than their Austro-Hungarian counterparts. The Serbian soldiers were also highly motivated, partially compensating for their lack of weaponry.
The Serbs beat back an Austro-Hungarian invasion in August at the Battle of Cer. That marked the first Allied victory over the Central Powers in World War I. Potiorek was humiliated by the defeat and was determined to resume the assault against the Serbs. He was permitted in September to launch another invasion of Serbia if he did not "risk anything that might lead to a further fiasco." Under pressure from the Russians to launch their offensive and to keep as many Austro-Hungarian troops as possible away from the Eastern Front, the Serbs invaded Bosnia in September with the help of Chetnik irregulars until being repulsed after a month of fighting in what came to be known as the Battle of the Drina. Bojović was wounded during the battle and was replaced by Živojin Mišić as commander of the Serbian 1st Army.
Prelude
Austro-Hungarian plans
The Armeeoberkommando (AOK) acknowledged that an undefeated Serbia severed Austria-Hungary's connection to the Ottoman Empire and prevented the completion of the Berlin–Baghdad railway. The AOK also realized that the Austro-Hungarian Army's inability to defeat Serbia would discourage neutral countries such as Bulgaria, Romania and Greece, from joining the Central Powers and would tempt Italy to open up a third front against Austria-Hungary. Nevertheless, the AOK hesitated to authorize a third invasion of Serbia. That changed in September 1914, when Austro-Hungarian troops discovered a map in an abandoned Semlin bookshop titled The New Division of Europe. Originally printed in a Russian newspaper, the map was widely sold in Serbia and depicted the borders of Europe as they would appear after the war. Germany was to be divided into northern and southern confederations. Austria-Hungary was to be abolished; its eastern provinces were to be ceded to Russia, Romania, the Czechs and the Hungarians; and its southern provinces were to be divided between Serbia and Italy. Alarmed by the prospect of Austria-Hungary's disintegration, Emperor Franz Joseph personally authorized a third invasion of Serbia in early October 1914.
Having just repelled the Serbian incursion into Bosnia, the Austro-Hungarian Army regrouped and positioned itself for one final invasion before winter set in. Potiorek was again placed in charge of Austro-Hungarian forces and was given command of the Austro-Hungarian 6th Army. The Austro-Hungarian 5th Army was commanded by Liborius Ritter von Frank. The Austro-Hungarians had 450,000 troops at their disposal. The Serbian army had 400,000 soldiers ready to face the Austro-Hungarian advance. Potiorek appeared confident: "Soldiers of the 5th and 6th armies, the goal of this war is nearly attained—the destruction of the enemy. The three-month campaign is almost over; we must only break the enemy's last resistance before the onset of winter". The Serbs were exhausted and demoralized. In a telegram to Putnik dated 27 October 1914, Stepanović complained that the 2nd Army did not have enough shells to resist the Austro-Hungarians effectively and requested to be removed from his command; Putnik denied the request, but ordered all units to resist the Austro-Hungarian advance for as long as possible before they retreated. That strategy had worked in Putnik's favour during the summer months until heavy rainfall in September and early October had reduced Serbia's roads to "muddy quagmires," making the movement of troops, guns and wagons increasingly hard. Potiorek recognized that the Serbian army was in a difficult situation; he was certain that a third invasion would bring him the decisive victory that he so desperately wanted.
In Vienna and Sarajevo, Austro-Hungarian officials began planning for the occupation and dismantling of Serbia. The country was to be plundered, with its territory used to bribe the neutral Balkan states into joining the Central Powers. The Romanians would get the region of the Timok Valley and the Bulgarians Macedonia and southeastern Serbia. The Austro-Hungarians intended to annex everything west of the Morava river, as well as the cities of Scutari (Shkodër) and Durazzo (Durrës), in northern Albania. The Serbs living west of the Morava, or "the compact masses of the Serbian element," as the Austro-Hungarians called them, were to be expelled and replaced with Austrian settlers, who would "change the psychology [of the region], making Serbia more Habsburg [and] less Serbian in outlook." Ludwig Thallóczy, the section chief of the Austro-Hungarian Finance Ministry, wrote Potiorek in October to recommend "the West Europeanization of the Serbs with a strong hand" as soon as Serbia had been occupied.
Potiorek planned to launch a converging attack across northern and western Serbia. The 5th Army was to capture Valjevo and envelope the Kolubara River from the north as the 6th Army was to secure the Jagodnja plateau and outflank Serbian units on the Kolubara from the south. The capture of the southeastern Serbian city of Niš was Potiorek's primary objective. Niš had been Serbia's capital since July and was a crucial transportation hub for its military. It also acted as a clearing house for munitions produced at the arsenal in Kragujevac. The city's capture would cut Serbia into two and scatter the Serbian army.
Third Austro-Hungarian invasion of Serbia
All of the valleys of northwestern Serbia were swamped by constant rainfall. The mountains had been covered in snow since early October. Acknowledging the opportunity such conditions presented, Putnik told his closest advisors: "All my strategy consists in placing the 'Serbian national mud' between the enemy's fighting line and his supplies." On 31 October, von Frank's 5th Army pushed into the region between the Sava and Drina rivers, while Potiorek's 6th Army drove west across the Drina and into the Jagodnja plateau. Austria-Hungary's third invasion of Serbia commenced on 6 November 1914, with intense artillery fire striking a series of Serbian border towns. On 7 November, the Austro-Hungarian 5th and 6th Armies attacked across the Drina. Outnumbered and in desperate need of ammunition, the Serbian army offered fierce resistance but was forced to retreat. The 3rd Army fell back against a road by the Jadar River to block the Austro-Hungarian advance towards Valjevo, and the 1st Army retreated southward into the Serbian interior. The Užice Army managed to prevent the Austro-Hungarians from crossing the Drina.
On 8 November, the Austro-Hungarians attacked the Serbian 2nd Army near Cer Mountain, coming within 1.6 kilometres (0.99 mi) of the Serbian frontline, entrenching themselves at the foot of the mountain. The 2nd Army was given orders to hold the Austro-Hungarians for as long as possible and, if its position became untenable, to retreat towards the right bank of the Dobrava River and position itself to block the approach to Valjevo. Elsewhere, the Austro-Hungarians drove a wedge between the 1st and the 3rd Armies and forced another Serbian retreat. Later that day, the Serbian government and the Serbian Supreme Command held a joint session concerning their worsening military position. Putnik stressed that Serbia needed to hold the Kolubara and the towns within its vicinity and suggested that the Serbs make a separate peace with Austria-Hungary if that proved impossible. That notion was rejected by Pašić, who urged further resistance to the Austro-Hungarians and threatened his government's resignation if peace discussions began. The session ended with the Serbian government and the Supreme Command agreeing to fight on.