Macedonian Front (World War I) - The Bulgarian Intervention and The Fall of Serbia

The Bulgarian Intervention and The Fall of Serbia

During the last year, the Serbs had tried, and failed to improve their supply situation. The Serbian Army had fielded a total of 420,597 men in the beginning of the war (Serbian Campaign (World War I)) and was considered veteran after its victories during the first (1912) and second Balkan wars which had ended a year before. For a year, the Allies (Britain and France) had repeatedly promised to send serious military forces to Serbia, while nothing had been realized. But with Bulgaria's mobilization to its south, the situation for Serbia became desperate. The developments finally forced the French and the British to decide upon sending a small expedition force of two divisions to help Serbia, but even these arrived too late in the Greek port of Salonika to have any impact in the operations.

The main reason for the delay was the lack of available Allied forces due to the critical situation in the western front, while the Greek government's insistence for neutrality was used as an excuse although the Albanian coast was also available for a rapid deployment of reinforcements and supplying of equipment during the past 14 months. As Marshal Putnik had suggested, the Albanian coast was adequately covered by the Montenegrin army to the north—being at safe distance from any Bulgarian advancing direction to the south—in case of a Bulgarian intervention. A second reason for the delay was the protracted secret negotiations with the hope to bring Bulgaria to the Allied camp, in which case no Allied help would be needed.

In any case the lack of Allied support sealed the fate of the Serbian Army. Against Serbia were marshalled the Bulgarian Army, a German Army, and an Austro-Hungarian Army, all under the command of Field Marshal Mackensen, totalling more than 800,000 soldiers. The Germans and Austro-Hungarians began their attack on October 7 with a massive artillery barrage, followed by attacks across the rivers. Then, on the 11th, the Bulgarian Army attacked from two directions, one from the north of Bulgaria towards Niš, the other from the south towards Skopje (see map). The Bulgarian Army rapidly broke through the weaker Serbian forces of the Vardar front, that tried to block its advance. With the Bulgarian breakthrough, the Serbian position became hopeless; either their main army in the north would be surrounded and forced to surrender, or it would try to retreat. Many high ranking Serbian officers were killed including Major Jovan Nikolic.

Marshal Putnik ordered a full retreat, south and west through Montenegro and into Albania. The weather was terrible, the roads poor, and the army had to help the tens of thousands of civilians who retreated with them. Only some 125,000 Serbian soldiers reached the coast of the Adriatic Sea and embarked on Italian transport ships that carried the army to various Greek islands (many went to Corfu) before being sent to Thessaloniki. Marshal Putnik had to be carried during the whole retreat and he died a bit more than a year later in a hospital in France.

The French and British divisions marched north from Thessaloniki in late November under the command of French General Maurice Sarrail. However, the British divisions were ordered by the War Office in London not to cross the Greek frontier. So the French divisions advanced on their own up the Vardar River. This advance was of some limited help to the retreating Serbian Army as the Bulgarian Army had to concentrate larger forces on their southern flank to deal with the threat (see: Battle of Krivolak). By mid-December, General Sarrail concluded retreat was necessary in the face of massive Bulgarian assaults on his positions. As with the British, the Germans ordered the Bulgarians not to cross the Greek borders reluctant to risk a Greek entrance to the war against a Bulgarian invasion in Macedonia. The Allies for their part took advantage of that, reinforcing and consolidating their positions behind the borders.

This was a clear, albeit incomplete victory for the Central Powers. As a consequence the railway from Berlin to Constantinople was opened and Germany was able to prop up its weak partner, the Ottoman Empire. A flaw in the victory was that the Allies managed to save a part of the Serbian Army, which although battered, seriously reduced and almost unarmed, escaped total destruction and after reorganizing was able to resume operations six months later. But the most damaging event for the Central Powers was that the Allies—using the moral excuse of saving the Serbian Army—managed to replace the impossible Serbian front with a viable one established in Macedonia (albeit by violating the territory of an officially neutral country); a front which would prove key to their final victory three years later.