October 1915-September 1918
The campaign is Salonika was tri-purpose: first to relieve pressure off of the Western Front; to persuade various Slavic states to join the Allies; and to help the Serbian Army. While not much was done in 1915, in the beginning months of 1916 the Allied forces dug in to keep from being pushed into the sea by the Austrian and Bulgarian forces. By the summertime, the Allied forces were joined by Serbian, Russian and Italian units. The attempted invasion of Greece by the Bulgarians failed when they were held off near Lake Dorian. In October 1916, Allied forces began to push forward on the River Struma towards Serres, eventually capturing Rupell Pass. The main area of fighting was around Dorian, and in April the British gained a large amount of ground and repulsed strong counter-attacks. In May, the British positions were attacked by Bulgarian forces, which were repulsed, but caused a series of attacks by Allied forces elsewhere, in the battle of Vardar. The front line remained more or less the same, but in 1918 a third offensive was begun. The British did not have much involvement until September, when they attacked Dorian and sustained heavy losses. The Serbian forces broke through west of the River Vardar, causing the Bulgarian Army to retreat. The campaign ended with the surrender of the Bulgarian Army on 30th September 1918..