The Balkan peninsula, is an area in south-east Europe that includes Albania, Greece, Bulgaria, Serbia, Montenegro, Macedonia and European Turkey. Tension in the area had been heightened by a series of local and international conflicts that culminated in the Balkan War.

In 1912 Greece, Serbia, Bulgaria and Montenegro won a series of comprehensive military victories over Turkish forces. The following year, Bulgaria, disappointed by the terms of the Treaty of London, attacked Greek and Serbian forces, but was quickly defeated when invaded by Romania. The subsequent peace treaty doubled the size of Serbia and gave Greece control over most of the Aegean coast.

The assassination of Archduke Franz Ferdinand at Sarajevo resulted in both Austria-Hungary and Germany declaring war on Serbia. On 25th August, Radomir Putnik and the Serbian Army defeated the Austro-Hungarian forces at the Battle of Jadar. With the support of its ally, Montenegro, Serbia managed to halt the advance of the Austro-Hungarian forces throughout 1914 including its important victory at the Kolubara River in December. However, these efforts virtually exhausted the Serbian Army's manpower and it was forced to recruit men over sixty. The army also accepted women, including the British nurse, Flora Sandes.

Serbia pleaded for help and eventually in September 1915, Britain and France accepted the invitation from the Greek prime minister, Eleutherios Venizelos, to land Allied troops at Salonika, a strategically important Greek port on the Aegean coast of Macedonia. As there was a direct railway link between Salonika and Belgrade, this became the best route to send Allied aid to Serbia.

The first Anglo-French troops arrived at Salonika on 5th October, 1915. With Bulgarian and German troops on the frontier, the French commander, General Maurice Sarrail and General George Milne, the leader of the British troops, turned Salonika and its surrounds into an entrenched zone. This included a trench-system similar to the one on the Western Front.

The arrival of Allied troops in Macedonia failed to stop the advance of the Central Powers in Serbia. Overwhelmed by the joint Austro-German and Bulgarian invasion in October 1915, the Serbian Army was forced to retreat to the Albanian mountains. By January 1916, over 155,000 Serbian soldiers and civilians had been evacuated to Corfu.

After recuperation, over 80,000 Serbian troops were sent to Salonika. Considered to be the most aggressive of all the allied troops, the Serbian Army took part in the victory over the Bulgarian Army at the Vardar Offensive in September 1918.