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The Salonika campaign

Page 4 – Campaign summary

The failure of the Anglo-French advance into Serbia in November 1915 forced the Allied forces to dig in on the outskirts of Salonika in case the Bulgarians attacked Greece. The hills surrounding the city and the outlying villages beyond were heavily fortified and surrounded by barbed wire once the weather improved in the spring of 1916. This series of defences became known to British troops as ‘The Birdcage’ because of the immense quantity of barbed wire used. Training was also undertaken to keep the troops occupied. Meanwhile, the shattered Serbian Army was being rebuilt and rearmed by the French on the island of Corfu in the Ionian Sea.

The anticipated Bulgarian invasion never took place. Instead, they too dug in from the Adriatic coast of Albania and along the Greek-Serb border to Lake Doiran on the Bulgarian border. Only in the far east of the front did the Bulgarians advance into Greece down the Struma Valley, occupying the area as far as the Ottoman border.

Opposing forces

The Salonika campaign (1915-1918) was fought between the Allies and Central Powers. Major participants included:

Allies: France, Greece (1917-1918), Italy (1916-1918), Montenegro (1915-1916), Russian Empire (1915-1917), Serbia, United Kingdom

Central Powers: Austria-Hungary, Bulgaria, German Empire, Ottoman Empire (1916-1917)

As part of the overall Allied offensive strategy in 1916, it was decided that the troops in Salonika would advance from the city against these Bulgarian positions. The first troops moved north in April, with the French taking up positions west of the Vardar River. Supported by Russian and Italian troops and later, the refitted Serbian Army, they captured the strategic town of Monastir on 19 November. The British Salonika Force (BSF), under its new commander Lieutenant-General George Milne, took up positions at Doiran and the British XVI Corps advanced into the Struma Valley to the east, from which the Bulgarians were in September. As this first spring and summer of campaigning wore on, large numbers of troops contracted malaria – endemic to the region – which was to severely weaken the Allied force throughout the campaign.

In April 1917, the Allies finally launched a major offensive. The main thrust was made by the Franco-Serb forces to the west, with the British launching a diversionary attack at Doiran to pin down Bulgarian units there. This latter attack by XII Corps went disastrously wrong against a determined foe manning elaborate mountainside defences and in the face of a breakdown in communications. A further attack in May also failed, as did the main attack by the Franco-Serbs to the west. The two attacks cost the British over 5000 men.

Following the failure of the spring offensive, the campaign settled down to stalemate with static warfare from Doiran to the west and mobile patrolling and raiding in the malaria-plagued Struma Valley. The British force was reduced, with several divisions sent to Egypt and France. When Greece officially joined the Allies in June 1917, some of these losses were offset. In the summer of 1918, as the tide turned against Germany on the Western Front and the Ottoman Empire in the Middle East, further offensive operations were planned for September by the new French commander at Salonika, General Franchet d’Esperey. The plan was similar to that of the previous year, and for the British at Doiran (augmented by two Greek divisions) it resulted in a similar catastrophe and over 7000 casualties.

In the west, however, Serbian forces broke through the Bulgarian lines and French cavalry advanced past them across undefended mountain passes. On 21 September, the British troops at Doiran realised the now outflanked Bulgarians facing them had retreated and were streaming across the mountains towards their own country, harassed by aircraft. With a collapse in civil order at home, the Bulgarian Army crumbled and on 30 September an armistice came into effect. Some British units from Salonika were then sent to other theatres, including the Russian Civil War and the Caucasus, from where some did not return until 1920.

The Salonika campaign was controversial both during and after the war, particularly in Britain. Many people at the time – and some historians subsequently – asked why so many troops remained tied down in the the British Salonika Force, apparently inactive, when they could have been better employed elsewhere against the Germans and the Ottoman Turks. The harsh climate and conditions and widespread malaria and dysentery took a toll on those who served there. Nevertheless, the defeat of Bulgaria turned out to be the first link in a chain of events leading to the end of the war on 11 November 1918. 

How to cite this page

Campaign summary, URL:, (Manatū Taonga — Ministry for Culture and Heritage), updated