In the 19th century, the national revival in the Balkans began; national and religious antagonism flared, and conflict was heightened by the Ottoman policy of playing one group against the other. Meanwhile, the Ottoman Empire lost control over the major sections of Greece, Serbia, and Bulgaria, each of which claimed Macedonia on historical or ethnical grounds.
In the Treaty of San Stefano (1878), which terminated the Russo-Turkish War of 1877–78, Bulgaria was awarded the lion's share of Macedonia. However, the settlement was nullified by the European powers in the same year (see Congress of Berlin), and Macedonia was left under direct Ottoman control.
After the Greco-Turkish war of 1897, which proved a disaster for Greece, Bulgarian nationalism started strengthening in Macedonia. Thus it came about that on the feastday (20 July) of the Prophet Elijah in 1903 there was a Macedonian uprising, known as the Ilinden Uprising, which the Ottoman army soon suppressed.
The rising, however, made plain the danger that Macedonia might be lost for ever, which stimulated a general mobilisation on the part of the Greeks. So it came about, in 1904, that the armed Greek Struggle for Macedonia began, lasting until 1908. During this period, units made up of volunteers from the free Greek state, from Crete and from other areas poured into region of Macedonia in solidarity with the local Makedonomáchoi (Greek: Μακεδονομάχοι, "Macedonian fighters"). Together, they confronted the Bulgarian forces in an attempt to assert hegemony over the central and southern parts of Macedonia.