This map is part of a series of 20 animated maps showing the history of The first World War, 1914-1918.
During the first year of the conflict, Serbia withstood the Austrian offensives after the declaration of war.
But in autumn 1915, the Central Powers, with their new Bulgarian partners, launched a combined offensive that led to the collapse of the Serbian front.
Franco‑British forces, transported from the Dardanelles to Salonika, were unable to link up with the Serbian army which was threatened with encirclement and was forced to make a dramatic retreat through the mountains of Montenegro and Albania.
The Serbian soldiers were picked up on the Adriatic coast by allied ships and taken to Corfu, then to Salonika. With the French and British troops, they formed the Army of the Orient, which remained in place until the offensive of autumn 1918.
For the time being, the Central Powers controlled the entire central area of the Balkans, and had at their disposal free communications with their Bulgarian and Turkish allies.