Battle of Florina ends

The British chronology of the war records under 19 August 1916 the end of the Battle of Florina, noting that it takes the name and dates of the engagement, 17–19 August, from the German list of battles. These three days covered the fastest part of the Bulgarian offensive in western Macedonia: the capture of Florina on 17 August, the failed Serbian counter-attack the following day and the Serbian retreat to the fortified hills above Lake Ostrovo. Yet the fighting by no means ended on 19 August. The Bulgarians, who speak of the Lerin or Chegan operation, count it as lasting until 27 August, when they halted their attacks, and Serbian accounts describe more than a week of heavy defensive fighting still to come.

On 18 August part of the Serbian Danube Division went over to the counter-attack near the village of Banica, on the railway from Florina to Salonika. According to the British official history of the operations in Macedonia, it ran into much stronger Bulgarian forces and was thrown back, and according to Serbian accounts it lost nine guns that day. On 19 August the Bulgarian 8th Division reached the foot of the Malka Nidže range and after heavy fighting took the Kirli Derven pass. In the afternoon the Bulgarians again attacked the Danube Division hard at Banica, and by the evening of the next day it had fallen back to the ridge west of Lake Ostrovo. Bulgarian accounts note that in front of them, a few hundred metres from their front line, three Serbian divisions now stood in fortified positions: the Drina, the Vardar and the Danube.

At the same time the Bulgarian Second Army was entering Greek Eastern Macedonia unopposed, and on the Struma a French detachment and British cavalry had to withdraw across the river. General Maurice Sarrail realised that his plan was out of date. On 20 August he called together the Allied commanders and decided to stand on the defensive on the Struma and the Vardar and to strike on the left wing, at Florina. The Italians were to relieve the French 57th Division, which together with the Russian brigade was sent to help the Serbs. The commander of the Serbian Third Army, General Pavle Jurišić Šturm, was relieved of his command.

The Bulgarians kept attacking at Lake Ostrovo for another week, on bare, waterless slopes, but the Serbs, brought up by rail and constantly reinforced with artillery, could not be dislodged. The British official history writes that the first blow took the Serbs by surprise, but their morale proved sound, and as soon as they had enough infantry and guns they calmly repulsed their old enemy. On 27 August the Bulgarian command ordered the attacks to stop and the troops to dig in. The success was only partial, however: Sarrail’s offensive was delayed by more than three weeks, but it was not stopped. On 12 September the Serbs, French and Russians went over to the attack, and at the end of the month the Serbs took Kaymakchalan, the peak that dominates the front.