During August 1916, the situation on the Eastern Front in the Balkans entered a new phase as Romania entered the war. Their declaration did not go unnoticed in Sofia. The Bulgarian high decided a show of force was required along the Macedonian Front, to shorten the front lines of the Central Powers, and to launch a pre-emptive attack against Entente forces preparing for an offensive in Salonika. On 17 August, the Bulgarian 1st Army launched the Chegan Offensive. Lerin was captured in short order, but after some ten days of fighting, the stated objectives were not realized. On 27 August, the operation was called off and the army was ordered to dig in on the positions between Lake Petursko, Lake Ostrovo and along the ridge of the Malka Nidzhe mountain it had occupied.
Attacker: Bulgarian (3rd Infantry Division, 1st Army)
