The Internal Macedonian Revolutionary Organization (IMRO; ; ) was a secret revolutionary society founded in the Ottoman territories in Europe that operated in the late 19th and early 20th centuries.Internal Macedonian Revolutionary Organization, written by Loring Danforth, an article in Encyclopedia Britannica Online.

It was founded in 1893 in Salonica and initially aimed to secure autonomy for Macedonia and Adrianople regions in the Ottoman Empire. However, it later became an agent serving Bulgarian interests in Balkan politics. IMRO modeled itself after the earlier Bulgarian Internal Revolutionary Organization of Vasil Levski and accepted its motto "Freedom or Death" (Свобода или смърть).Duncan M. Perry, The Politics of Terror: The Macedonian Liberation Movements, 1893–1903, Duke University Press, 1988, , pp. 39–40. According to the Organization's earliest statute from 1894, the membership was reserved exclusively for Bulgarians. This was later changed on the initiative of Gotse Delchev, who wanted IMRO to depart from its exclusively Bulgarian nature, so he opened the membership for all inhabitants of European Turkey, and the organization began to acquire a more separatist stance.Vladimir Crețulescu (2016) "The Memoirs of Cola Nicea: A Case-Study on the Discursive Identity Construction of the Aromanian Armatoles in Early 20th Century Macedonia." Res Historica 41, p. 128.Victor Roudometof (2002) Collective Memory, National Identity, and Ethnic Conflict. Greece, Bulgaria, and the Macedonian Question. Bloomsbury Academic, , pp. 94, 112. Delchev sought autonomy for Macedonia under the slogan Macedonia for the Macedonians. However, these new formulas as a whole failed to attract other ethnic groups, as they generally perceived it as "the Bulgarian Committee";Dimitar Bechev, Historical Dictionary of the Republic of Macedonia, Scarecrow Press, 2009, , Introduction, p. Iviii.Tchavdar Marinov, Famous Macedonia, the Land of Alexander: Macedonian identity at the crossroads of Greek, Bulgarian and Serbian nationalism in Entangled Histories of the Balkans - Volume One: National Ideologies and Language Policies with Roumen Daskalov and Tchavdar Marinov as ed., BRILL, 2013, , p. 300. eventually, IMRO's base remained only among Bulgarian millet-affiliated Slavic speakers in Ottoman Macedonia and in Adrianople vilayet. It used the Bulgarian language in all its documents and in its correspondence. The Organisation established its Foreign Representation in 1896 in Sofia. Starting in the same year, it fought the Ottomans using guerrilla tactics, and in this, they were successful, even establishing a state within a state in some regions, including their tax collectors. This struggle escalated in 1903 with the Ilinden–Preobrazhenie Uprising. The fighting involved about 15,000 IMRO irregulars and 40,000 Ottoman soldiers, lasting for over seven weeks. After the uprising failed, and the Ottomans destroyed some 100 villages, the IMRO resorted to more systematic forms of terrorism targeting civilians. More importantly, the Ilinden disaster splintered IMRO and signalled the beginning of a fratricidal conflict between the left-wing faction ("federalists") who continued to favor autonomy as a step towards independent Macedonia and its inclusion into a future Balkan Federation, and the right-wing faction ("centralists") which favored unification with Bulgaria. In fact, the division was a culmination of a conflict which existed within IMRO since its formation. It was based partially on ideology, and partly in terms of personality and locality, and it would plague the Macedonian revolutionary movement over the next decades.

During the Balkan Wars and the First World War, the organization supported the Bulgarian army and joined Bulgarian wartime authorities when they temporarily took control over parts of Thrace and Macedonia. IMRO's adherents regarded the division of the area among the Balkan states in the Balkan Wars not as "liberation", but as entailing the partition of Macedonia.Viktor Meier (1999). Yugoslavia: A History of Its Demise. Routledge. p. 179. . Retaining the unity of Macedonia seemed crucial for IMRO in this period; autonomism as a political tactic was abandoned, and annexationist positions were supported, aiming eventual incorporation of occupied areas into Bulgaria. The desire to incorporate most of Macedonia and Thrace within a Bulgarian state lay behind the Bulgarian decision to enter each of these three wars. The Bulgarian government first attached the IMRO chetas as auxiliaries of its army in the Balkan wars and then drafted the former paramilitaries directly into it, as Bulgarian military personnel during the First World War. Under the right-wing leadership, IMRO arose then from a clandestine organization into an important factor of the Greater Bulgarian policy, supporting the Bulgarisation of the area. Additionally, some guerrilla companies formed by IMRO-irregulars participated in several massacres of accused Serbomans in the areas of Azot, Skopska Crna Gora and Poreče. Regular Bulgarian troops took control of the region while komitadjis were appointed mayors or prefects and served as gendarmerie corps. IMRO detachments participated in the suppression of the Serbian Toplica uprising. Nevertheless, the division within IMRO during this period continued to exist, and the wars reinforced the rival federalist and unionist tendencies in the IMRO factions. These two tendencies were consequently adopted in the interwar period, the first one by the "federalist" wing and the latter by the "centralist" wing.

After World War I, the combined Macedonian-Thracian revolutionary movement separated into two detached organizations, IMRO and ITRO. Simultaneously, the "federalists" split up and formed the Macedonian Federative Organization and later IMRO (United). After this, the IMRO earned a reputation as an ultimate terror network, seeking to change state frontiers in the Macedonian regions of Greece and Serbia (later Yugoslavia). They contested the partitioning of Macedonia and launched raids from their Petrich stronghold into Greek and Yugoslav territory. Their base of operation in Bulgaria was jeopardized by the Treaty of Niš, and the IMRO reacted by assassinating Bulgarian prime minister Aleksandar Stamboliyski in 1923, with cooperation of other Bulgarian elements who organised a coup d'état. In 1925, the Greek army launched a cross-border operation to reduce the IMRO base area, but it was ultimately stopped by the League of Nations, and IMRO attacks resumed. A conflict over the leadership arose and Ivan Mihailov ordered the assassination of Aleksandar Protogerov, which sparked a fratricidal war between the so called "Mihailovists" and "Protogerovists". By 1928, after the assassination of Protogerov, Mihailov proposed a new plan calling for unification of a pre-1913 Macedonia region into a single state, that would be independent from Bulgaria.Todor Chepreganov et al., History of the Macedonian People, Institute of National History, Ss. Cyril and Methodius University, Skopje,(2008) p. 254. In the interwar period the IMRO also cooperated with the Croatian Ustaše, and their ultimate victim was Alexander I of Yugoslavia, assassinated in France in 1934. After the 1934 Bulgarian coup d'état, their Petrich stronghold was subjected to a military crackdown by the Bulgarian army, and the IMRO was reduced to a marginal phenomenon. According to Ivan Katardžiev, practically, neither the left nor the right wing of the IMRO questioned their Bulgarian provenance and Dimitar Vlahov would do so only in 1948 at a Politburo's session of the Macedonian Communist Party.Денко Малески: Иван Катарџиев: Верувам во имунитетот на македонскиот национален идентитет. Фокус, декември 8, 2023 г.

The organization changed its name on several occasions, but the name VMRO (IMRO) remained most noted. After the fall of communism in the region, numerous parties claimed the IMRO name and lineage to legitimize themselves. Among them, the right-wing parties established in the 1990s, "VMRO-BND" in Bulgaria and "VMRO-DPMNE" in then Republic of Macedonia.

Ottoman era

Origins and goals

The organization was a secret revolutionary society operating in the late 19th and early 20th centuries with the goal of autonomous Macedonia and Adrianople regions. It was founded in 1893 in Ottoman Thessaloniki by a small band of anti-Ottoman Macedono-Bulgarian revolutionaries, who considered Macedonia an indivisible territory and all of its inhabitants "Macedonians", no matter their religion or ethnicity, thus signaling the emergence of a new, firmly Macedonian national movement. In practice, IMRO was established by Bulgarians in Macedonia and the vast majority of their followers were Slavic speakers in Ottoman Macedonia, of whom primarily Bulgarian Exarchists. At that time IMRO was often called "the Bulgarian Committee",Julian Allan Brooks (2013) Managing Macedonia: British Statecraft, Intervention and 'Proto-peacekeeping' in Ottoman Macedonia, 1902-1905. Simon Fraser University, p. 143. while its members were designated as Comitadjis, i.e. "committee men".The word komitadji is Turkish, meaning literally "committee man". It came to be used for the guerilla bands, which, subsidized by the governments of the Christian Balkan states, especially of Bulgaria. For more see: The Making of a New Europe: R.W. Seton-Watson and the Last Years of Austria-Hungary, Hugh Seton-Watson, Christopher Seton-Watson, Methuen, 1981, , p. 71. Initially, it was against the irredentist aspirations of neighboring states in the area. From its foundation, IMRO was evidently torn apart by political and ideological factionalism, members shared significantly conflicting views concerning Macedonia, Macedonians, and their relation with Bulgaria. Some of them saw the autonomy evolving into independent Macedonia, that would become a member of a future Balkans federal state. Others saw the outcome of the autonomy as unification of Macedonia and Adrianople with Bulgaria.Идеята за автономия като тактика в програмите на национално-освободителното движение в Македония и Одринско (1893–1941), Димитър Гоцев, 1983, Изд. на Българска Академия на Науките, София, 1983, c. 34.; in English: The idea for autonomy as a tactic in the programs of the National Liberation movements in Macedonia and Adrianople regions 1893–1941", Sofia, Bulgarian Academy of Sciences, Dimitar Gotsev, 1983, p. 34. Among others, there are used the memoirs of the IMRO revolutionary Kosta Tsipushev, where he cited Delchev, that the autonomy then was only tactics, aiming future unification with Bulgaria. (55. ЦПА, ф. 226); срв. К. Ципушев. 19 години в сръбските затвори, СУ Св. Климент Охридски, 2004, стр. 31–32. in English: Kosta Tsipushev, 19 years in Serbian prisons, Sofia University publishing house, 2004, , p. 31-32. The idea of autonomy was strictly political and did not imply a secession from Bulgarian ethnicity. Even those, who advocated for independent Macedonia and opposed Greater Bulgaria, never doubted the predominantly Bulgarian character of the Macedonian Slavs. The organization was founded by Hristo Tatarchev, Dame Gruev, Petar Pop-Arsov, Andon Dimitrov, Hristo Batandzhiev and Ivan Hadzhinikolov. All of them were closely connected with the Bulgarian Men's High School of Thessaloniki.