From the winter of 1907 to the spring of 1908, the situation in Western Macedonia had deteriorated considerably for the Greek Macedonian fighters. The Ottomans had hardened their attitude toward the Greek Orthodox population of Vilaetio Monastir (now Bitola), making several arrests of chiefs and soldiers and frequently committing acts of violence against villages that maintained their faith in the Ecumenical Patriarchate. At the same time, the forces of the Exarchist armed corps operating in the wider region of Macedonia seem to have been strengthened.

In an effort to meet the above challenges, as well as the additional difficulties created for the Macedonian fighters by the withdrawal of Georgios Tsontos (Captain Vardas) and the general disorganization of the Greek forces in Vilayeti Monastir, the Macedonian Committee responded by organizing and sending two new armed corps to Western Macedonia. The first consisted of forty-four hoplites and was commanded by the experienced Cretan chieftain Georgios Dikonymo-Makris, who had been in Athens since November 1906 due to an injury. The second, consisting of about twenty men, was commanded by Lieutenant Loukas Papaloukas (Captain Roumeliotis).

On April 23, 1908, the day of the feast of St. George, the two corps met in the village of Vantsiko (now Kydonies) and continued their activities together. A few days later, they were reinforced by the twelve-man corps of chieftain Evangelos Koropoulis and the corps of chieftain Georgios Souliou. The combined forces of the Greek chieftains decided to attack Kastanochoria from Kostenets (now Ieropigi), which was an important center of activity for the Bulgarian Cets.

The attack in Kostenetsi took place on the night of May 12-13. The Greek Macedonian fighters, under the command of Dikonymos-Makris and Captain Roumeliotis, divided into smaller groups and attacked from the west and east, surrounding the village. During the ensuing operation, the Macedonian corps inflicted significant casualties on the Exarchists, killing about 40 and burning about 27 houses with bombs and oil. Greek losses amounted to 2 dead and a few wounded, including chieftains Charalampopoulos and Pentheroudakis.

The battle of Kostenetsy ended with the arrival of the Ottoman cavalry sent from Biglista (now Viglista in Korytsa, Albania). The strong presence of the Ottoman army forced the corps of Dikonymos-Makris, which was fighting in the west, to retreat towards the Korestia region and, avoiding ambushes by the Ottoman army in the villages of the area, finally lay in Vitsi at the end of May. Papaloukas' corps, fighting in the east, fled further south to Kastanochoria, where it continued to engage in fighting until the Young Turk Revolution in July 1908.