Battle of Cer

Background

Austria-Hungary declared war on Serbia on 28 July 1914, a month after the assassination of Archduke Franz Ferdinand in Sarajevo. The Habsburg general staff under Conrad wanted a quick war of punishment in the Balkans, but Russia's mobilisation forced it to send most of the army north to Galicia. Oskar Potiorek, governor of Bosnia and commander of the Balkan forces, was left with the Fifth and Sixth Armies. The Second Army, the northern army along the Sava and Danube, was his only until 18 August, when it was due to leave for the Russian front. Without it Potiorek had about 280,000–290,000 men to cover some 900 km of frontier.

Potiorek wanted a fast victory anyway, ideally by the Emperor's birthday on 18 August. Rather than strike at Belgrade from the north, where the Serbs expected him, he chose to attack from the west. The Fifth Army would cross the Drina and the Sava into the Mačva plain and the Jadar valley and drive on Valjevo. The Sixth Army would come over the upper Drina further south, and the Second Army would make a demonstration across the Sava at Šabac. General Frank of the Fifth Army asked for a two-day delay to finish concentrating, and Potiorek refused. The attack opened on 12 August.

The Serbian chief of staff, Vojvoda Radomir Putnik, had been caught by the war at a spa in Austria and allowed home. He kept the bulk of his army back in Šumadija, from where it could turn north or west once he knew where the main blow was falling.

The armies

Potiorek's striking force was Frank's Fifth Army: VIII Corps from Prague under Arthur Giesl von Gieslingen (9th Infantry and 21st Landwehr Divisions) and XIII Corps from Zagreb (36th Infantry and 42nd Home Guard Divisions). From the Second Army, IV Corps from Budapest crossed at Šabac, and the 29th Division was also drawn in. Many units came straight off long train journeys and hard marches in great heat, before their supply, ammunition and medical trains had arrived, and VIII Corps had bridging for only one of its two Drina crossings. Up to half the men of the Fifth and Sixth Armies were Croats and Serbs from the Monarchy's southern districts. Giesl's 21st Landwehr Division was largely Czech.

Putnik had four armies: the First (Bojović), Second (Stepa Stepanović), Third (Pavle Jurišić Šturm) and the Užice Army. The Second and Third bore the battle. Their best formations were first-levy divisions such as the Combined, Morava and Šumadija Divisions, with the Cavalry Division and second-levy troops such as the Timok Division. About 185,000 Serbs were veterans of the Balkan Wars of 1912–13. Equipment was thin: one estimate gives the field army about 180,000 modern rifles, 200 machine guns and three aircraft. The Serbs were experienced, tough and clever in defence, and they were fighting on their own ground.

The battle

The invasion, 12–15 August. This is CDB90's engagement The Jadar, which runs from the first crossings on 12 August to 20 August. On 12 August the Fifth Army crossed the Drina at Loznica and Lešnica, with XIII Corps on the southern crossings. VIII Corps met heavy fire from the far bank. To the north, the Second Army's IV Corps crossed the Sava and took Šabac. The columns pushed east at right angles to the rivers and ridges, through scrub, forest and maize two metres high. By 14 August the invaders were across on a front of about 160 km, converging on Valjevo. Putnik had expected the main attack from the north, but by 15 August he had read it. He ordered a counter-attack, and Stepanović's Second Army made a forced march through the night of 15–16 August to join the hard-pressed Third Army.

The night battle on the Cer, 15–16 August. The Cer is a wooded ridge between the Jadar valley and the Mačva plain. Its slopes had been occupied only lightly by the 21st Landwehr Division. At about 23:00 on 15 August the leading troops of the Combined Division ran into its outposts near Tekeriš. By midnight a confused hand-to-hand fight was raging in the dark. By morning the Serbs held the Divač range and had driven the Austro-Hungarians out of Borino Selo. Around 13:00 on 16 August, near Tekeriš, a Serbian battalion ambushed the 57th Brigade, and the 21st Division was pushed off the Cer.

Šabac and the Jadar, 17–18 August. On 17 August a Serbian attempt to retake Šabac failed. The Combined Division attacked Trojan and Parlog and turned towards Kosanin Grad, the high point of the ridge. In the Jadar valley the Third Army was pushed back and had to shift a division to cover Valjevo against the 42nd Home Guard Division. On 18 August an Austro-Hungarian attack out of the Šabac bridgehead was beaten on the Dobrava stream. That day the Serbian Second Army opened its counter-offensive along the Cer and the Iverak ridge.

Collapse, 19–20 August. At dawn on 19 August the Serbs took Kosanin Grad. The Morava Division drove off the 9th Division. IV Corps could not break the Šumadija Division to reach the Cer. Rašulijača was retaken at noon, then Velika Glava, and the Rajin Grob ridge by late afternoon. The 21st Landwehr Division was in disarray, and the Fifth Army began to withdraw. On 20 August its troops were streaming back across the Drina, many drowning in the crossing. Potiorek had meant his Sixth Army to fall on the Serbian flank from the south, but its offensive was held up by the terrain and the blow never came.

Šabac retaken, 21–24 August. IV Corps still held Šabac. After two days of hard fighting on its western approaches, the Serbs closed round the town on 23 August and brought up siege guns that evening. The garrison left in the night. The Serbs entered Šabac on 24 August and reached the Sava by 16:00. No invader remained in Serbia except prisoners.

Aftermath

Austro-Hungarian losses in less than two weeks were about 600 officers and over 22,000 men killed, wounded and captured, including some 4,500 prisoners. Other works put them much higher, at up to 44,500. Serbian losses were about 16,300 by one count and 18,000–20,000 by others. The Serbs also took guns, machine guns and ammunition wagons. Stepanović was promoted vojvoda, field marshal, for the battle.

It was the first Allied victory of the war. Potiorek kept his command and was allowed a second invasion in September, but only on condition that he took no risks. In Vienna the defeat was blamed on Czech disloyalty in the 21st Landwehr Division. There was an inquiry, martial law was imposed, and Giesl was relieved about two weeks later. Rauchensteiner argues that Giesl and his men were the least to blame.

The fighting also brought a wave of violence against Serbian civilians. In the Mačva, Austro-Hungarian troops killed an estimated 3,500–4,000 Serbs in executions and random violence during the brief occupation. At Šabac on 17 August about 120 townspeople, mostly women, children and old men, were shot and buried in a churchyard. At Lešnica a pit was later found holding 109 bound and shot peasants. The Swiss criminologist R. A. Reiss documented the killings for the Serbian government.

Cer is remembered in Binički's March on the Drina and the 1964 film of the same name, and in the 1928 ossuary at Tekeriš.

Wargaming it

Cer is a meeting engagement fought along a single ridge, and it suits games at brigade or division level. Use turns of half a day and hexes or squares of 1–2 km. A board from the Drina at Loznica east to Šabac and the Dobrava, with the Cer and Iverak ridges across the middle, holds the whole battle. The night of 15–16 August makes a good stand-alone tactical game at battalion level: a Serbian division marching blind into thinly held outposts on wooded slopes, with a need for night-fighting rules for confusion, friendly fire and lost units.

The key terrain is the Cer crest, Kosanin Grad and Rajin Grob, which dominate the Jadar valley to the south and the Mačva to the north. Whoever holds them sees and shells both. Rivers matter too. The Austro-Hungarians fight with the Drina and Sava at their backs, on too few bridges, which makes retreat a disaster.

The interesting rules concern logistics and command. The invaders should start tired, short of food, ammunition and bridging, with columns moving across the grain of the country through maize and scrub. Potiorek's player must also manage the Second Army as a wasting asset, with IV Corps liable to be withdrawn. What ifs: Frank gets his 48-hour delay; the Second Army stays and attacks in strength from Šabac; the Sixth Army attacks on 15 August rather than 20 August; Putnik guesses wrong and waits in the north.

Maps and pictures

Pictures from the time

Photographs by the armies' photographers and the press, and drawings made at the time: free-to-use pictures from the battle's category on Wikimedia Commons. Each opens its file page there, with the full caption and source.