In August 1916,
Romania chose to join the war effort on the side of the
Allies. The Allies planned a large offensive in the
Macedonian front for the middle of August to support Romania's entry into the war and pin down as many Bulgarian forces as possible. The Bulgarian high command suspected an impending offensive, and the fighting around
Doiran that erupted on 9 August only confirmed these suspicions. On their part, the Bulgarians had urged for an offensive in Macedonia since the beginning of the year, now planning a strike with the
First Army and
Second Army on both Allied flanks. On the western flank, the
Chegan Offensive resulted in the conquest of
Florina, but the First Army failed to take Chegan (today
Agios Athanasios). The plan on the eastern flank was to seize the
Drama-Komotini railway, and this objective was given to the
Bulgarian Second Army and the 10th Aegean Division. For the operation
General Todorov could rely on 58 battalions, 116 machine guns, 57 artillery batteries and five cavalry squadrons in his army and an additional 25 battalions, 24 machine guns, 31 batteries, and five squadrons in the 10th Division. == Occupation and consequences ==