Conquest of Serbia

The conquest of Serbia was the swiftest and most complete campaign of the Central Powers in 1915. A year earlier the small Serbian army had three times repelled an Austro-Hungarian invasion, and in December 1914 it routed the invaders on the Kolubara. In the autumn of 1915, however, Serbia faced three states at once. On 6 October the German Eleventh Army and the Austro-Hungarian Third Army, under the joint command of Field Marshal August von Mackensen, struck across the Sava and the Danube, and a week later Bulgaria attacked from the east. In less than two months the Central Powers’ forces occupied the whole country. The French and British, who had landed at Salonika, were unable to break through to the north. The Serbian army, however, did not allow itself to be surrounded. Together with the king, the government and thousands of refugees, it withdrew across the snow-covered mountains of Montenegro and Albania to the Adriatic.

Name and dates

This page uses the dates 6 October – 4 December 1915. The start is the day on which Mackensen’s artillery began the bombardment proper of the Serbian positions on the rivers and the first Austro-Hungarian units crossed the Drina and the Sava. German lists of battles also begin the “campaign in Serbia” on 6 October. English-language works often give 7 October, when the main forces forced the rivers near Belgrade, and some give 5 October, when the artillery began ranging. Serbian sources, which used the Julian calendar, date the start of the invasion to 23 and 24 September.

The end is harder to pin down. Many works end the campaign on 24 or 25 November, when the Germans and Austrians took Pristina and Mitrovica and Mackensen halted the pursuit. German lists of battles close it for individual divisions between 22 and 28 November. The Bulgarians, however, pursued the Serbs further, around Prizren and Đakovica, and according to the Austrian official history broke off the pursuit only on 4 December in order to turn against the French and British in Macedonia. This page takes that day as the end of the campaign. The retreat of the Serbian army across the Albanian mountains, known in Serbia as the Albanian Golgotha, went on until January 1916.

In Serbia the 1915 campaign is also called the “triple invasion”, because the country was attacked by three states. It should not be confused with the third Austro-Hungarian invasion of autumn 1914, which ended in defeat on the Kolubara.

Background

After the defeats of 1914 Austria-Hungary did not have the strength to defeat Serbia on its own, and from May 1915 it also had to fight Italy. For most of the year the Serbian front was quiet. Germany, however, needed Serbia for another reason. Across its territory ran the railway from Hungary through Belgrade, Niš and Sofia to Constantinople, and Turkey, defending itself at the Dardanelles, was short of ammunition. The chief of the German General Staff, Erich von Falkenhayn, who later called himself the author of the whole undertaking, wanted above all to open this route. For that Bulgaria was needed. When in the summer of 1915 the Russians were retreating in Poland and the Allies were stuck at Gallipoli, Sofia decided that it had chosen the right side. On 6 September it concluded an alliance with Germany, and the military convention provided for a joint attack on Serbia under Mackensen’s command. In return Bulgaria was to receive Serbian Macedonia.

Mackensen, the victor of Gorlice, arrived in Temesvár on 20 September. On the northern side of the Danube stood the German Eleventh Army of General Max von Gallwitz, seven divisions in three corps, facing Smederevo and Ram. On the Sava and the Drina deployed the Austro-Hungarian Third Army of General Hermann Kövess, who at the end of September had replaced General Karl Tersztyánszky. It had the Austro-Hungarian VIII Corps facing Belgrade, the German XXII Reserve Corps west of the city, XIX Corps on the Sava, and several groups made up mainly of the territorial reserve, the Landsturm, on the lower Drina and near Višegrad. In the east, beyond the Bulgarian border, the First Army of General Kliment Boyadzhiev was concentrating, four huge divisions subordinated to Mackensen. Further south the Second Army of General Georgi Todorov, reporting directly to the Bulgarian command, was to enter the Vardar valley and cut the Serbs’ railway to Salonika, their only link with the outside world.

According to the Austrian official history, Mackensen’s army group and the Bulgarian Second Army together numbered 350 battalions and 1,400 guns. The Serbs had 275 battalions and 654 guns. The British official history cites Falkenhayn’s calculation: 330,000 rifles against 190,000. The Serbian army had not yet recovered from the losses of 1914 or from the epidemic of typhus which in the winter and spring of 1915 had killed tens of thousands of people.

The Serbs had to divide their forces into two almost equal parts. In the north stood the First Army of Vojvoda Živojin Mišić in Mačva and on the Drina, the Belgrade defence troops of General Mihailo Živković, and the Third Army of General Pavle Jurišić Šturm on the Danube. Against the Bulgarians stood the Timok Army and the Second Army of Vojvoda Stepa Stepanović, while Macedonia was defended only by weak units, largely made up of recruits and volunteers. The chief of staff of the supreme command was still the ailing Vojvoda Radomir Putnik. The Serbian command wanted to strike at the Bulgarians before they completed their mobilisation, but the British and Russians, who still hoped to win Sofia over, categorically forbade it. In return the Entente promised help. On 5 October French and British troops began landing at Salonika, but they were still hundreds of kilometres from the Serbian front.

Course

Across the rivers, 6–11 October. The Central Powers’ artillery began ranging on 5 October, and on the afternoon of 6 October it opened fire along the whole length of the front, from Orsova to Višegrad. That day the first units of the Austro-Hungarian Landsturm crossed the Drina near Bijeljina and the Sava near Jarak, and on the night of 6–7 October the main crossings began. At Belgrade the Austro-Hungarian 59th Infantry Division landed at the foot of the Kalemegdan fortress, and the German XXII Reserve Corps on the islands in the Sava. For two days and nights the landing force clung to the riverbank under the defenders’ fire, supported by the monitors of the Danube Flotilla. On 9 October the Serbs abandoned the capital. Further east the Eleventh Army crossed on 7 October at Ram, on 8 October at Kostolac, and on 9 October at Smederevo, which it took on 11 October. The advance of XIX Corps on the Sava and of the Landsturm groups on the Drina, by contrast, bogged down in marshes, amid floods and under Serbian counter-attacks.

The Košava and the Bulgarians, 12–22 October. Mackensen’s forces advanced slowly. From 12 October the autumn košava raged over the Danube, a wind that tore away the pontoon bridges and for several days almost cut the armies off from their rear. The Serbs defended every ridge south of Belgrade and near Požarevac, which they abandoned only in the middle of the month. On 11 October the Bulgarians provoked clashes on the border, and on 14 October Bulgaria declared war on Serbia and both its armies went over to the attack. For many days Boyadzhiev could not break the defence in the mountains on the Timok and near Pirot, but Todorov’s Second Army quickly entered Macedonia. On 16 October it took Vranje and cut the railway from Niš to Salonika; over the following days it reached the Vardar near Veles, and on 22 October it took Skopje. Serbia was cut off from its allies. On 20 October the Austro-Hungarian Landsturm entered Šabac, abandoned by the Serbs, without a fight, and at the end of the month the Germans and Bulgarians cleared the bank of the Danube as far as Prahovo. According to the Austrian official history, by 25 October the waterway from Hungary to Bulgaria was open.

Kragujevac and Niš, 23 October – 7 November. Mackensen wanted to trap the main Serbian forces in a pocket around Kragujevac, the seat of the headquarters and of the country’s only arsenal. Putnik, however, did not allow himself to be encircled. On 31 October the Serbs blew up the arsenal and withdrew southwards, and on 1 November the Germans entered the town. On 5 November the Bulgarians took the abandoned city of Niš, Serbia’s wartime capital, and on 7 November the Germans marched into Kruševac. The Central Powers’ forces joined up along the whole front and by 9 November controlled the railway from Belgrade to Sofia. Mackensen then began sending some of the German divisions to other fronts.

The Kosovo Field, 8–25 November. The Serbian army fell back into the mountains south of the Morava, towards the Kosovo Field, the site of the famous battle against the Turks in 1389. The Central Powers’ forces pressed it from the north, east and south. In the south the French of General Maurice Sarrail reached only the area of Krivolak in the Vardar valley and halted before the Bulgarian positions. The Serbs made one more attempt to break through to them via the gorge at Kačanik, but after two days of heavy fighting, on 21 November, the Bulgarians drove them back. On 23 November the Germans took Pristina, and the Austrians almost simultaneously Mitrovica. On 24 November Mackensen gave his exhausted troops a rest and did not intend to pursue the Serbs into the Albanian mountains. Between 23 and 25 November the Serbian government and supreme command decided that the only salvation was a retreat across the mountains of Montenegro and Albania to the Adriatic, from where the Allies were to evacuate the army.

The retreat, from 25 November. The army withdrew by three routes: through Peć and Montenegro to Scutari, through Prizren and the mountains of northern Albania, and further south towards Durrës. Artillery that could not be taken along the mountain paths was abandoned or buried. The Bulgarians pursued the rearmost columns near Prizren and Đakovica, took thousands of prisoners, and broke off the pursuit only on 4 December. At the beginning of December King Peter I, carried in an ox cart, and Putnik, borne in a litter by soldiers, reached Scutari. With the army went crowds of refugees and thousands of Austro-Hungarian prisoners taken in 1914. Tens of thousands of people died of hunger, frost and disease, or in attacks by Albanian highlanders.

Losses

Exact losses cannot be given. According to the Austrian official history, Serbia fielded during the campaign, including replacements, about 340,000 men and lost about 94,000 killed and wounded. By the end of November the German and Austro-Hungarian armies had taken more than 124,000 prisoners, and the Bulgarians about 50,000, along with hundreds of guns. According to the same source Austria-Hungary lost about 18,000 killed, wounded and missing. German losses are estimated at some ten to twenty thousand men, and Bulgarian losses, according to Bulgarian works, at about 37,000. Serbian estimates of the losses during the retreat through Albania speak of tens of thousands of dead soldiers and an even greater number of civilians, although these figures are uncertain.

Significance

The Central Powers achieved the goal for which they had launched the campaign. The Danube was open to transports to Bulgaria and Turkey by the end of October, and according to the Austrian official history the railway from Belgrade to Constantinople was passable along its whole length from mid-January 1916. Serbia was divided into Austro-Hungarian and Bulgarian zones of occupation. In January 1916 Austria-Hungary attacked Montenegro, which soon capitulated.

The Central Powers did not fully achieve their military goal. The Serbian army was not destroyed. At the beginning of 1916 Allied ships carried more than a hundred thousand of its soldiers from the Albanian coast to the Greek island of Corfu. There they rested and received new weapons, and later they fought on the Salonika front, from which they returned home in 1918. For the Entente the fall of Serbia was a heavy defeat, especially a diplomatic one. Despite their promises, the Allies did not come to the Serbs’ aid in time, and the expedition to Salonika, undertaken too late and with too few forces, left in the Balkans a front that was to last until the end of the war.