Bulgaria and Serbia declare war on each other

On 14 October 1915, that is 1 October according to the Julian calendar which Bulgaria then used, Tsar Ferdinand issued a manifesto to the nation on war with Serbia. Bulgaria entered the world war on the side of Germany, Austria-Hungary and Turkey. After more than a year of neutrality and bargaining between the two sides, it chose the Central Powers, which had promised it what the Entente could not give: the whole of Serbian Macedonia. For a week Serbia had been defending itself in the north against the armies of Field Marshal August von Mackensen. Now it was attacked from the east as well.

The British chronology of the war records that on this day Bulgaria and Serbia declared war on each other. The initiative, however, came from Sofia, and Serbia had already been fighting the Bulgarians on the frontier for several days. The British official history of the Macedonian campaign states that Bulgaria declared war on 13 October and marched a day later. Most sources, Bulgarian ones included, adopt the date of the manifesto: 14 October.

The manifesto

The manifesto was signed by the Tsar and countersigned by all the ministers, headed by the prime minister, Vasil Radoslavov. It presented Bulgaria as the victim of aggression. Both warring groups of powers, the Tsar said, had recognised the great wrong done to the Bulgarians by the partition of Macedonia after the Second Balkan War, and both agreed that the greater part of that land should belong to Bulgaria. Only “our perfidious neighbour, Serbia” had remained unmoved by the advice of its friends and allies, and in its envy and greed had attacked Bulgarian territory, so that “our gallant troops” had to defend their own soil.

“The European war is drawing to a close,” Ferdinand proclaimed. The victorious armies of the Central Powers were already in Serbia and advancing rapidly. The Tsar called on the nation and the army to defend the country “defiled by a perfidious neighbour” and to free “our enslaved brothers” from the Serbian yoke. “Our cause is just and holy,” he wrote, and he ordered the army to drive the enemy from the kingdom’s borders and crush him together with the troops of the central empires.

The claim that Serbia had attacked Bulgaria was a pretext. According to the Austro-Hungarian official history, on 11 October it was the Bulgarians who provoked a clash with Serbian frontier guards in order to have a reason for war. The version of a Serbian attack also mattered for Greece. The Greek-Serbian alliance of 1913 obliged Athens to help if Serbia were attacked by Bulgaria, and the Greek government had a few days earlier refused the Serbs help, arguing that the 1913 alliance did not cover a war against several great powers at once.

The attack

Bulgaria had been ready for war for several days. Under the military convention of Pless it was to attack Serbia within 35 days of its signature, and by then it had to mobilise and deploy its army. Meanwhile the armies of Field Marshal Mackensen, who commanded all the forces against Serbia, had crossed the Sava and the Danube, but were advancing slowly south of Belgrade.

On 14 October both Bulgarian armies went over to the attack. The First Army of General Kliment Boyadzhiev, subordinated to Mackensen, struck at eastern Serbia: at fortified Zaječar and Pirot, and through Knjaževac towards Niš, where the Serbian government had sat since the previous year. The Second Army of General Georgi Todorov advanced into Serbian Macedonia to cut the railway from Niš to Salonika. In the east the Serbs defended themselves fiercely on the high frontier ridges, and rain, snow and fog slowed the attack. In weakly defended Macedonia the Bulgarians moved faster. As early as 15–16 October they reached Vranje and cut the railway to Salonika.

Serbia found itself in the position its commander-in-chief, Vojvoda Radomir Putnik, had long warned of. Its army, numbering fewer than 250,000 men, had to fight on two fronts against superior forces. When in September Putnik had wanted to strike at the Bulgarians before they finished mobilising, the Allies forbade him. Entente help was only just being unloaded at Salonika.

Reactions

That same afternoon the British Foreign Secretary, Edward Grey, made a statement in the House of Commons on Allied policy in the Balkans. He said that the Entente had sought an understanding among the Balkan states, but could not promise Bulgaria as much as Germany was giving it at others’ expense. He announced that Serbia, which was “fighting for her existence”, would receive every possible help. The next day Britain and Montenegro declared war on Bulgaria, France on 16 October, and Russia and Italy on 19 October.

In Bulgaria itself, according to reports that reached the ailing Russian minister Alexander Savinsky, the war with Serbia aroused none of the enthusiasm of 1912, and the first fighting at Pirot brought heavy losses. Within a few weeks, however, the Bulgarians, together with the Germans and Austrians, conquered Serbia, and its army retreated through the mountains of Albania to the Adriatic.