The Internal Macedonian Revolutionary Organization (IMRO; Bulgarian: Вътрешна македонска революционна организация (ВМРО), romanized: Vatreshna Makedonska Revolyutsionna Organizatsiya (VMRO); Macedonian: Внатрешна македонска револуционерна организација (ВМРО), romanized: Vnatrešna Makedonska Revolucionerna Organizacija (VMRO)), was a secret revolutionary society founded in the Ottoman territories in Europe, that operated in the late 19th and early 20th centuries.

[2] Founded in 1893 in Salonica,[3] it initially aimed to gain autonomy for Macedonia and Adrianople regions in the Ottoman Empire, however, it later became an agent serving Bulgarian interests in Balkan politics.

– Means The organization was founded in 1893 in Ottoman Thessaloniki by a small band of anti-Ottoman Macedono-Bulgarian revolutionaries,[20] who considered Macedonia an indivisible territory and all of its inhabitants "Macedonians", no matter their religion or ethnicity.

Ivan Hadzhinikolov in his memoirs lists the five basic principles of the MRO's foundation: According to Dr. Hristo Tatarchev: We talked a long time about the goal of this organization and at last we fixed it on the autonomy of Macedonia with the priority of the Bulgarian element.

We couldn't accept the position for "direct joining to Bulgaria" because we saw that it would meet big difficulties by reason of confrontation of the Great powers and the aspirations of the neighbouring small countries and Turkey.

The region of Adrianople, as far as I remember, didn't take part in our program, and I think the idea to add it to autonomous Macedonia came later.In Dame Gruev's memoirs, the MRO's goals are stated as follows: We grouped together and jointly worked out a statute.

In the regulations, there was nothing concerning the Serbian propaganda but we intended to counteract it by enlightening the people.The Adrianople Region was the general name given by the Organization to those areas of Thrace which, like Macedonia, had been left under Turkish rule i.e. most of it, where the Bulgarian element predominated in the mixed population, too.

The organized revolutionary movement in Thrace dates from 1895, when Dame Gruev recruited Hristo Kotsev, born in Shtip, who was then a teacher in the Bulgarian Men's High School of Adrianople.

[44] The stated goal of the original Committee was to unite all elements dissatisfied with the Ottoman oppression in Macedonia and the Adrianople Vilayet, eventually obtaining political autonomy for the two regions.

[13] In the words of British contemporary observer Henry Brailsford: When, in addition to these advantages, the Bulgarophil Macedonians started their marvellously-organised revolutionary committee in 1893, the Servian cause received its death-blow.

The Servian movement is a purely official agitation, guided and financed in Belgrade; whereas, despite the sympathy of Sofia, the Bulgarian Revolutionary Committee is a genuine Macedonian organisation.What is more, some of its younger leaders espoused radical socialist and anarchist ideas and saw their goal as the establishment of a new form of government rather than unification with Bulgaria.

[15] In regard to the socialist and cosmopolitan ideas within the revolutionary movement, the American Albert Sonnichsen says: I think that was the force of the abstract thought, that they kept in their mind, a thought which was far from chauvinism, because freedom for them stood higher than the rule of the Bulgarian, for them it was one perfect system equally applicable to Bulgarians, Greeks and Turks, a kind of heaven to which the whole world should aim.It is claimed by contemporary historians that the right wing supporters within the IMRO were probably much more likely to see unification with Bulgaria as a natural final outcome of Macedonian autonomy.

The second one staged an ill-fated uprising in Eastern Macedonia in 1902, where they were opposed militarily by local SMARO bands led by Yane Sandanski and Hristo Chernopeev, who were later to become the leaders of the IMARO left-wing.

In August 1903 SMARO organised the Ilinden-Preobrazhenie Uprising against the Ottomans in Macedonia and the Adrianople Vilayet, which after the initial successes including the forming of the Krushevo Republic, was crushed with much loss of life.

The Supreme Macedonian Committee was disbanded in 1905 but the centralist faction of the IMARO drifted more and more towards Bulgarian nationalism as its regions became increasingly exposed to the incursions of Serb and Greek armed bands, which started infiltrating Macedonia after 1903.

Later, the congress for MARO's official inauguration failed and federalist wing joined mainstream political life as the Peoples' Federative Party (Bulgarian Section) (PFP).

[56] At the end of 1915 and the beginning of 1916 several massacres of (sic) Serbomans were conducted in Vardar Macedonia in the areas of Azot, Skopska Crna Gora and Poreče by IMRO-irregulars, aided by the guerrilla companies of the 11th Macedonian Infantry Division.

The Bulgarian Prime Minister Aleksandar Stamboliyski favoured a détente with Greece and Yugoslavia, so that Bulgaria could concentrate on its internal problems, and preferred the creation of a Balkan Federation.

On 23 March 1923 Stamboliyski signed the Treaty of Niš with the Kingdom of Serbs, Croats and Slovenes and undertook the obligation to suppress the operations of the IMRO carried out from Bulgarian territory.

[62] In 1923 and 1924 during the apogee of interwar military activity according to IMRO statistics in the region of Yugoslav (Vardar) Macedonia operated 53 chetas (armed bands), 36 of which penetrated from Bulgaria, 12 were local and 5 entered from Albania.

[31] In this interwar period IMRO led by Aleksandrov and later by Mihailov took actions against the former left-wing assassinating several former members of IMARO's Sandanist wing, who meanwhile had gravitated towards the Bulgarian Communist Party and the Macedonian Federative Organization.

Dimo Hadzhidimov, Arseni Yovkov, Vladislav Kovachev, Aleksandar Bujnov, Chudomir Kantardzhiev, Stojo Hadzhiev, Georgi Skrizhovski and many others were killed in the aftermath of the May Manifesto.

The conflict grew into a leadership struggle and Mihailov soon, in turn, ordered the assassination in 1928 of a rival leader, General Aleksandar Protogerov, which sparked a fratricidal war between "Mihailovists" and "Protogerovists".

The policy of assassinations was effective in making Serbian rule in Vardar Macedonia feel insecure but in turn provoked brutal reprisals on the local peasant population.

It was also anticipated that the IMRO volunteers would form the core of the armed forces of a future Independent Macedonia in addition to providing administration and education in the Florina, Kastoria and Edessa districts.

After the declaration of war by Bulgaria on Germany, in September 1944 Mihailov arrived in German-occupied Skopje, where the Germans hoped that he could form a pro-German Independent State of Macedonia with their support.

Many of the left-wing IMRO government officials, including Pavel Shatev and Panko Brashnarov, were purged from their positions, too, then isolated, arrested, imprisoned or executed by the Yugoslav federal authorities on various (in many cases fabricated) charges including: pro-Bulgarian leanings, demands for greater or complete independence of Yugoslav Macedonia, collaboration with the Cominform after the Tito–Stalin split in 1948, forming of conspirative political groups or organisations, demands for greater democracy, etc.

One of the victims of these campaigns was Metodija Andonov Cento, a wartime partisan leader and president of ASNOM, who was convicted of having worked for a "completely independent Macedonia" as an IMRO member.

Delchev and Sandanski were adopted as symbols of the republic, had numerous monuments built in their honor, and they were often the topic of articles in the academic journal Macedonian Review, as was the Ilinden Uprising.

A small spin-off from VMRO-BNM existed between 2010 and 2014, named VMRO – National Ideal for Unity (ВМРО – Национален идеал за единство), or ВМРО–НИЕ (VMRO-NIU), which used VMRO-BND's flag.