Struma operation



The Struma operation was a successful offensive operation of the Bulgarian army during the First World War between 17–23 August 1916 in which they conquered all Greek territory east of the Struma river.

Background
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 in order to support Romania's entry in 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 and now planned 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 el).

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 5 cavalry squadrons in his army and an additional 25 battalions, 24 machine guns, 31 batteries and 5 squadrons in the 10th Division.

Battle and consequences
The Struma Offensive began on 18 August with the 7th Rila, 11th Macedonian Division and the 3/2 Infantry Brigade and 10th Division advancing on a 230 kilometer long front. For six days the Bulgarian forces achieved all their objectives in the face of weak Greek and French resistance: following the ouster of pro-Entente Prime Minister Eleftherios Venizelos, the royal Greek government in Athens had demobilized it forces, and pursued a course of neutrality at all costs, even ordering the local Greek troops to not resist the Bulgarian invasion.

The depth of the advance reached 80-90 kilometers and an area of 4,000 square kilometers was occupied. Most importantly however the Macedonian Front was shortened with 100 - 120 kilometers and the Greek IV Army Corps, numbering 464 officers and 6373 soldiers that was positioned in the area but wasn't allowed by the Greek government to resist, was disbanded and its troops and armament were interned by the Germans in Silesia for the rest of the war. The cities of Kavala, Drama and Serres were taken.

The refusal by the Greek government to defend this territory, won after hard fighting in the Second Balkan War of 1913, against the hated Bulgarians, led to a coup by pro-Venizelist officers and the formation of the Provisional Government of National Defence.