Balkan Front of World War 1: Serbia and the Salonika Campaign

The Balkan front of World War 1 is the theatre where the Great War began and where it first started to fall apart. On 28 July 1914 Austria-Hungary declared war on Serbia, the first declaration of war of the entire conflict. And on 29 September 1918, in Salonika, Bulgaria signed an armistice and became the first Central Power to leave the war. Between those two dates came three repelled invasions, the winter retreat of an entire army across the mountains of Albania, and a three year deadlock at Salonika that Berlin dismissed as its largest internment camp, right up to the moment it collapsed the whole southern flank.

This article is for readers who follow World War 1 history and want a proper account of a front that most textbooks cover in two paragraphs. At the end we look at which Balkan lessons carry over into Frontkrieg, a free browser grand strategy game set in 1914.

The Balkan front in brief

• The war's first shot was fired here, on 28 July 1914, one month after the shooting in Sarajevo.
• In 1914 Serbia repelled three Austro-Hungarian invasions in a row and retook Belgrade on 15 December.
• In autumn 1915 a combined German, Austro-Hungarian and Bulgarian blow forced the Serbian army to retreat across the Albanian mountains in winter.
• The Salonika front stretched roughly 400 kilometres and barely moved for three years.
• On 15 September 1918 the Allies broke through at Dobro Pole, and within two weeks Bulgaria was out of the war.

Why the Balkans became the first front of the Great War

Europe had called this region a powder keg long before 1914. The two Balkan Wars of 1912 and 1913 redrew borders, left Bulgaria embittered towards its neighbours, doubled Serbia in size and turned it into Vienna's principal irritant. When Archduke Franz Ferdinand was shot in Sarajevo on 28 June 1914, the Austrian government finally had the pretext it had been waiting for.

What followed was the chain of alliances we unpack in detail in our piece on the causes of World War 1. One detail matters most: a local punitive expedition against a small country became a continental war within a week. Serbia, with a pre-war population of roughly 4.5 million, sat at the centre of a conflict fought by empires dozens of times its size.

1914: how Serbia survived three invasions

The Austro-Hungarian command expected to be done in a few weeks. It did not work out that way.

The Battle of Cer

On 16 August 1914 the Serbian army under General Stepa Stepanovic met the Austrians on the Cer mountain range. The fighting lasted until 19 August and ended with Austro-Hungarian troops pulling back across the Drina. This was the first Entente victory of the entire war, won two weeks before the Battle of Tannenberg concluded on the Eastern Front.

The Kolubara operation

The Austrians tried twice more that autumn. In November they even entered Belgrade. But on 3 December 1914 the Serbian army, resupplied with fresh ammunition, counterattacked on the Kolubara river and drove the enemy out of the capital on 15 December. Six months into the war, Serbia was still holding the line against a neighbour of more than 50 million people.

The cost was appalling. Through the winter of 1914 and 1915 a typhus epidemic swept the country and is estimated to have killed more than 100,000 people, including civilians and prisoners of war. The army that had won three battles came out of that winter drained of strength.

1915: Bulgaria, Mackensen and the winter retreat

In autumn 1915 the Central Powers came back with a different plan. Bulgaria joined the war on their side on 14 October, and Serbia suddenly had a second front at its back. German and Austro-Hungarian armies under Field Marshal August von Mackensen advanced from the north while Bulgarian forces pushed in from the east, together around 300,000 men.

The Serbian army faced a choice: surrender or march. It marched. Through the autumn and winter of 1915 the troops, together with tens of thousands of civilians, withdrew over the mountain passes of Albania and Montenegro towards the Adriatic. Serbian history remembers that march as the Albanian Golgotha. Of the more than 200,000 people who set off into the mountains, roughly 150,000 reached the coast. The rest died of cold, hunger, typhus and attacks along the way.

Allied ships evacuated the survivors to the Greek island of Corfu. A few months later the reorganised Serbian army was shipped to a new front at Salonika. It is one of the rare cases in history of an army without a state returning to the war and fighting through to victory.

The Salonika front: three years without movement

An Anglo-French force had already landed at Salonika in Greece on 5 October 1915, while the country was still formally neutral. That landing created the front known by two names: the Salonika front and the Macedonian front.

It ran for roughly 400 kilometres of mountain country from Albania to the Struma river. French, British, Serbian, Italian and Russian troops fought here, joined by Greek forces from 1917. By 1918 the Allied Army of the Orient numbered around 600,000 men. The German command joked that it was maintaining the largest internment camp in the world: a huge Allied army standing in the mountains for years, apparently affecting nothing.

The main enemy was not bullets but malaria. Losses to disease on this front vastly exceeded combat casualties, and entire divisions were out of action for months at a time. For contrast, on the Italian Front it was mountain artillery that ground men down, while on the Eastern Front manoeuvre and space decided outcomes.

September 1918: how the Balkans broke the Central Powers first

On 15 September 1918 Allied forces under General Louis Franchet d'Esperey launched the Vardar Offensive. The main blow fell on the Bulgarian positions at Dobro Pole. The mountain terrain that had favoured the defence for three years turned against it once the line was pierced: the Bulgarian front had no second position in depth.

After that events came as an avalanche. Within two weeks the Bulgarian army had fallen back, and on 29 September 1918 the Armistice of Salonica was signed, taking effect at noon on 30 September. Bulgaria became the first Central Power to quit the war.

The consequences reached far beyond the Balkans. The southern flank of the Central Powers collapsed, the road towards Hungary and the Romanian oil fields opened, and the Ottoman Empire lost its land link to Germany. A little over a month later the Ottomans signed an armistice, then Austria-Hungary, and finally Germany on 11 November. We covered that endgame separately in our article on the 1918 armistice and the Treaty of Versailles. On 1 November 1918 Serbian troops entered Belgrade, the city they had left three years earlier.

The total cost to Serbia is put by various counts at around 1.1 million military and civilian dead, roughly a quarter of the pre-war population. These are the heaviest proportional losses of any belligerent, and the full figures appear in our overview of World War 1 casualties.

What the Balkan front teaches a Frontkrieg player

The Balkans in Frontkrieg look much as they did in 1914: a dense cluster of small provinces, mountains, several neighbours at once. Three lessons from this theatre translate into game mechanics almost intact.

• A second front decides more than raw numbers. Serbia held against Austria-Hungary for a year and broke in weeks once Bulgaria joined. The same holds in game: a coalition attacking from two directions stretches a stronger player's defence thin. How to negotiate that kind of joint blow is covered in our diplomacy and alliances guide.
• Distance from the capital hits your rear areas. In Frontkrieg province morale drops by 8 points for every step away from your capital, the distance penalty is capped at 35 points, and a freshly captured province starts at 25 morale. Below 10 morale a province revolts and turns neutral. That is exactly why deep breakthroughs without consolidating the rear end the way the Austrian entry into Belgrade ended in November 1914.
• Terrain and logistics weigh more than they look. Armies move through enemy territory at roughly 0.35 of base speed and through allied territory at about 0.70, while a province with a railway grants a 50 percent march speed bonus. A roadless mountain dead end is precisely what kept the Salonika front frozen for three years.

The in-game map covers 4,800 provinces, up to 500 live players and 70 AI-run nations, so the Balkan scenario of a small country surrounded plays out almost daily. Where the historical borders fall on that map is shown in our breakdown of the 1914 map of Europe.

Frequently asked questions

What was the Salonika campaign during World War 1?

It was the theatre in the southern Balkans created by the Anglo-French landing at Salonika in Greece on 5 October 1915. The front, roughly 400 kilometres long, lasted three years and ended with the Vardar Offensive of September 1918, which knocked Bulgaria out of the war.

Which countries helped Serbia in World War 1?

Serbia was backed by the Entente powers: France, Britain, Russia and Italy, along with allied Montenegro. French and British warships evacuated the Serbian army from the Albanian coast to Corfu in the winter of 1916, after which it was re-equipped and returned to the line at Salonika.

How many Serbians died in World War 1?

Estimates vary, but the most commonly cited figures put Serbian losses at around 1.1 million military and civilian dead, roughly 25 percent of a pre-war population of about 4.5 million. That is the highest proportional death toll of any country in the war.

What was the Armistice of Salonica?

It was the agreement signed by Bulgarian and Allied representatives on 29 September 1918, effective at noon on 30 September. Under its terms Bulgaria ceased hostilities, demobilised its army and opened its territory to Allied forces. It was the first exit of a Central Power from the war.

Conclusion

The Balkan front of World War 1 was not a sideshow but the frame around the whole conflict: the war began here in July 1914 and began ending here in September 1918. Serbia's story shows that a small state can hold a front for years against an incomparably stronger enemy until a second blow lands from behind, and that an army which has lost its territory has not yet lost the war.

If you want to test those patterns yourself, play the Balkans out on the 1914 map. A new match in Frontkrieg starts every day, the game is free with no pay-to-win, and it runs straight in the browser. More front histories and mechanics breakdowns are collected on our blog.

Sources: World War I and the Macedonian front on Wikipedia.