Gotse Delchev in the context of Adrianople Thrace

Gotse Delchev (Bulgarian: Гоце Делчев [ˈɡɔt͡sɛ ˈdɛɫt͡ʃɛf]), is a town in Gotse Delchev Municipality in Blagoevgrad Province of Bulgaria.

In 1951, the town was renamed after the revolutionary leader Gotse Delchev. It had hitherto been called Nevrokop (in Bulgarian: Неврокоп, Nevrokop; in Greek: Άνω Νευροκόπι, romanized: Ano Nevrokopi, lit. 'Upper Nevrokopi'; and in Turkish: Nevrokop).

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.

Founded in 1893 in Salonica, it sought sovereignty for Macedonia under the slogan Macedonia for the Macedonians. Initially it 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. IMRO modeled itself after the earlier Bulgarian Internal Revolutionary Organization of Vasil Levski and accepted its motto "Freedom or Death" (Свобода или смърть). According to the memoirs of some founding and ordinary members, in 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 begun to acquire a more separatist stance. However, these new formulas as a whole failed to attract other ethnic groups, from whom it was seen as a pro-Bulgarian society, thus IMRO remained with base only among Bulgarian Exarchist affiliated Slavic speakers in Ottoman Macedonia. It used the Bulgarian language in all its documents and in its correspondence. The Organisation founded in 1896 its Foreign Representation in Sofia, the capital of Bulgaria. 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 important, 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 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.

Yane Ivanov Sandanski (Bulgarian: Яне Иванов Сандански, Macedonian: Јане Иванов Сандански, romanized: Jane Ivanov Sandanski; Originally spelled in older Bulgarian orthography as Яне Ивановъ Сандански (Yane Ivanov Sandanski); 18 May 1872 – 22 April 1915) was a Macedonian Bulgarian revolutionary and leader of the left-wing of the Internal Macedonian-Adrianople Revolutionary Organisation (IMARO).

In his youth Sandanski was involved in the anti-Ottoman struggle, joining initially the Supreme Macedonian-Adrianople Committee (SMAC), but later switched to IMARO by pledging his loyalty to Gotse Delchev. As an activist of the Liberal Party (Radoslavists), at that time he became the head of the local prison in Dupnitsa. He was the mastermind behind the abduction of American Protestant missionary Ellen Stone in order to secure funds for IMARO. After the Ilinden Uprising, Sandanski became the leader of the Serres revolutionary district and of the socialist inspired left-wing ("federalist") faction of IMARO. With his superior leadership he managed to establish a "state within the state" in northeastern Macedonia. The left-wing advocated for the establishment of an independent Macedonian political entity after the autonomy, and the creation of a Balkan Federation, attaining equality for all its subjects and nationalities. Sandanski and the left-wing also vigorously resisted the idea of unification of Macedonia with Bulgaria. During the Second Constitutional Era he became an Ottoman politician, collaborating with the Young Turks and founding the People's Federative Party. Sandanski took up arms on the side of Bulgaria during the Balkan Wars (1912–13). Afterwards, he became involved in Bulgarian public life again, supporting the Democratic Party, but began plotting to assassinate the Bulgarian Tsar Ferdinand I and was executed by the rivalling IMARO right-wing faction activists on the order of Todor Aleksandrov.

In the earliest dated samples of statutes and regulations of the clandestine Internal Macedonian Revolutionary Organization (IMRO) discovered so far, it is called Bulgarian Macedonian-Adrianopolitan Revolutionary Committees (BMARC). These documents refer to the then Bulgarian population in the Ottoman Empire, which was to be prepared for a general uprising in Macedonia and Adrianople regions, aiming to achieve political autonomy for them. In thе statute of BMARC, that itself is most probably the first one, the membership was reserved exclusively for Bulgarians. This ethnic restriction matches with the memoirs of some founding and ordinary members, where is mentioned such a requirement, set only in the Organization's first statute. In fact, the founders of IMRO were sympathetic to Bulgarian, but hostile to the Serbian nationalism, which led them to establish in 1897 a Society against Serbs. The organization's ethnic character is confirmed by the lack of any mention of Macedonian ethnicity. The name of BMARC, as well as information about its statute, was mentioned in the foreign press of that time, in Bulgarian diplomatic correspondence, and exists in the memories of some revolutionaries and contemporaries.

Due to the lack of original protocol documentation, and the fact its early organic statutes were not dated, the first statute of the Organisation is uncertain and is a subject to dispute among researchers. The dispute also includes its first name and ethnic character, as well as the authenticity, dating, validity, and authorship of its supposed first statute. Moreover, in North Macedonia, any Bulgarian influence on the country's history is a source of ongoing disputes and sharp tensions, thus such historical influences are often rejected by Macedonian researchers in principle. Certain contradictions and even mutually exclusive statements, along with inconsistencies exist in the testimonies of the founding and other early members of the Organization, which further complicates the solution of the problem. It is not yet clear whether the earliest statutory documents of the Organization have been discovered. Its earliest basic documents discovered for now, became known to the historical community during the early 1960s.