According to a 1911 Ottoman census, there were 350,000 Greeks, 246,000 Bulgarians and 456,000 Muslims in the vilayet of Manastır,https://web.archive.org/web/20060527053759/http://www.univ.trieste.it/~storia/corsi/Dogo/tabelle/popolaz-ottomana1911.jpg 1911 Ottoman census however the basis of the Ottoman censuses was the millet system where people were assigned an ethnicity according to their religion. Therefore, all Sunni Muslims were categorised as "Turks" even though many of them were Albanians, while all members of the Greek Orthodox church were listed as "Greeks" although this group was composed of Aromanians, Slavs, and Tosk Albanians, in addition to the Greeks which were numbered at ~100,000. The Slavic-speakers were divided between the Bulgarian majority and a small Serbian minority."Serbian propaganda in Monastir was, however, then only in its infancy, and nothing but very elementary school books were to be had. The Bulgarians had a big school and church. If anyone had suggested that Monastir was Serb or ever likely to be Serb, people would have thought him mad—or drunk. The pull was between Greek and Bulgarian, there was no mention of the Serbs. There was a large "Greek" population, both in town and country, but of these a very large proportion were Vlachs. Many were South Albanians, others were Slavs. Few probably were genuine Greeks. But they belonged to the Greek branch of the Orthodox Church, and were categorized as Greek in the census. Those Slavs who called themselves Serbs, and the Serb schoolmasters who had come for propaganda purposes, all went to the Greek churches."Ortaylı, İlber. "Son İmparatorluk Osmanlı (The Last Empire: Ottoman Empire)", İstanbul, Timaş Yayınları (Timaş Press), 2006. pp. 87–89. .
