He was born in 1868 in the village of Bogomila, near Veles. He was one of the leaders of the student protest in the Bulgarian Men's High School of Thessaloniki in 1887/1888. The reason was the disagreement with the controversial policy led by the Bulgarian Prime Minister Stefan Stambolov, which was also promoted by the school authorities. The students aimed to replace lecturing in standard Bulgarian with the local Macedonian dialects.[9] As a consequence, he was expelled along with 38 other students. Then they accepted the offer to study for free at the expense of the Serbian society "St. Sava" in Belgrade.[10] He managed to enroll in the philology studies program at Belgrade University in 1888, but due to the resistance to Serbianisation, the group was once more evicted in 1890 and moved to Sofia.[11] In 1892 he graduated in Slavistics from Sofia University. In 1891 he is one of the founders of Young Macedonian Literary Society in Sofia and its magazine Loza (The Vine).[12] One of the purposes of the magazine of Young Macedonian Literary Society was to defend the idea the dialects from Macedonia to be more represented in Bulgarian literature language. The authors of this magazine clearly considered them as Macedonian Bulgarians.[13][14][15] However, the Stambolov government suspected them of lack of loyalty and some separatism, and the magazine was promptly banned by the Bulgarian authorities after several issues.
Petar Poparsov with his former students on an excursion near Kostenets during 1921.
Afterwards he became an active participant in the so-called "Committee for Obtaining the Political Rights Given to Macedonia by the Congress of Berlin" from which, as Petar Poparsov wrote, later developed the IMARO. According to Poparsov the brutal policy of Serbianization, which denied all human dignity in the Macedonian Bulgarians was the main reason for its creation.[16][17] In 1894 Petar Poparsov was asked by the founders to prepare a draft for the first statute of the IMARO, based on the Statute of Vasil Levski's Internal Revolutionary Organization, which was available to them in Zahari Stoyanov's Notes on the Bulgarian Uprisings.[18] Some international, Macedonian and Bulgarian researchers assume, that in this first statute the organization was called Bulgarian Macedonian-Adrianople Revolutionary Committees, and Poparsov was its author.[19][20][21] The membership in the first statute was allowed only for Bulgarians.[22]
From 1896 to 1897 he worked in Štip as a Bulgarian teacher and president of the regional IMARO section. In 1897 he was arrested by Ottoman authorities on charges of inciting rebellion, and sentenced to 101 years in prison. He was pardoned in August 1902. During the wave of arrests that followed the Thessaloniki bombings of 1903, Poparsov was arrested in Veles and taken to Skopje prison.[23] For this reason he did not participate in the following Ilinden-Preobrazhenie Uprising. At the Rila Congress of IMRO in November 1905, he was admitted to the organization’s Foreign Representation in Sofia.[24] Poparsov is considered to have been among the leftist federalist faction of the revolutionary organization, favoring political autonomy of Macedonia and strongly opposed to the ring-wing centralist faction which favored unification with Bulgaria.[25] After the Young Turk revolution of 1908, he took an active part in the preparation and holding of the elections for the Ottoman Parliament with the list of the People's Federative Party (Bulgarian Section) but did not receive the necessary number of votes for a deputy. During the First Balkan War he participated in an unsuccessful meeting attended by some local revolutionaries from the IMARO in Veles. It was organized by Dimitrija Čupovski and its aim was to authorize representatives to participate in the London peace conference, with the goal of preserving the integrity of the region of Macedonia.[26]
His last name is sometimes rendered 'Poparsov' or 'Pop Arsov'. In the older Bulgarian orthography, his name was spelled as Петъръ попъ Арсовъ. Also known in the Serbian historiography as Petar Pop Arsić.[1]
Peter Kardjilov, The Cinematographic Activities of Charles Rider Noble and John Mackenzie in the Balkans (Volume One) Cambridge Scholars Publishing; ISBN9781527550735, 2020, p. 3.
(...)The almost exclusive "national" basis of the Internal organization was namely the Exarchist population. The same holds true for the clear domination of the Exarchist social elite within its leadership and of the practical support given to it by the local institutions of the Exarchate. Bulgarian teachers in Macedonia constituted the backbone of the Internal organization while, according to their social profile, its leaders were quite often themselves former Exarchist teachers. (...) The lack of diverse "ethnic" motivations is confirmed by the fact that, in his brochure ("Stambolovism in Macedonia and its representatives" issued in 1894), Poparsov generally used the designations "Bulgaro-Macedonians" and "Macedonian Bulgarians" in order to name his "compatriots." For more see: Tchavdar Marinov We, the Macedonians. The Paths of Macedonian Supra-Nationalism (1878–1912) p. 107-137 in We, the People: Politics of National Peculiarity in Southeastern Europe with Mishkova Diana as ed., Central European University Press, 2009, ISBN9639776289.
ВМОРО през погледа на нейните основатели. Спомени на Дамян Груев, д-р Христо Татарчев, Иван Хаджиниколов, Антон Димитров, Петър Попарсов (in Bulgarian). Съст. Т. Петров, Ц. Билярски. София, 2002, с. 203-207.
Macedonia: A Voyage through History (Vol. 2, From the Fifteenth Century to the Present), Volume 2, Cambridge Scholars Publishing, 2016, ISBN9781443888493, p. 131.
Ванчо Ѓорѓиев, Петар Поп Арсов: прилог кон проучувањето на македонското националноослободително движење (in Macedonian), Матица македонска, 1997, ISBN9789989481031, p. 195.
Ѓорѓиев, Ванчо (1995). Петар Поп Арсов. Прилог кон проучувањето на македонското националноослободително движење (in Macedonian). Skopje. p.13.{{cite book}}: CS1 maint: location missing publisher (link)
ВМОРО през погледа на нейните основатели. Спомени на Дамян Груев, д-р Христо Татарчев, Иван Хаджиниколов, Антон Димитров, Петър Попарсов. Съст. Т. Петров, Ц. Билярски. София, 2002, с. 203-207.
"Although they did not agree so enthusiastically with the character of standard Bulgarian language that was quite distant from Macedonian dialects, the editors of the review suggested that, according to their language, the Macedonians “may only be Bulgarians.”" Marinov, Tchavdar. We, the Macedonians: The Paths of Macedonian Supra-Nationalism (1878–1912) in: We, the People: Politics of National Peculiarity in Southeastern Europe. Budapest: Central European University Press, 2009, p. 121.
"Though Loza adhered to the Bulgarian position on the issue of the Macedonian Slavs' ethnicity, it also favored revising the Bulgarian orthography by bringing it closer to the dialects spoken in Macedonia." Historical Dictionary of the Republic of Macedonia, Dimitar Bechev, Scarecrow Press, 2009, ISBN0810862956, p. 241.
The Young Macedonian Literary Association's Journal, Loza, was also categorical about the Bulgarian character of Macedonia: "A mere comparison of those ethnographic features which characterize the Macedonians (we understand: Macedonian Bulgarians), with those which characterize the free Bulgarians, their juxtaposition with those principles for nationality which we have formulated above, is enough to prove and to convince everybody that the nationality of the Macedonians cannot be anything except Bulgarian." Freedom or Death, The Life of Gotsé Delchev, Mercia MacDermott, The Journeyman Press, London & West Nyack, 1978, p. 86.
"The brutal policy of Serbianization, which denied all human dignity in the Macedonian Bulgarians and severely hurt their national feeling, was clearly patronized by the representatives of the Russian Tsar and actively supported by the government of the Turkish Sultan, which artificially created affairs and pushed the Bulgarians into prisons and exiles, took away their churches and schools, created a tragedy in the soul of this million-strong Bulgarian people, which became even more terrible considering that the annexation meant not only denationalization, but also the return of the Macedonian Bulgarians under the authority of the Greek patriarchate, against which they had led years of bloody struggle and had barely escaped her vampiric clutches. The slogan was: Away from Bulgaria! Not because she was to blame for the situation in Macedonia, but because any suspicion of her intervention could harm both her and the case, which had to retain its purely internal Macedonian character. On these clear and well-defined foundations was formed the first secret Committee for acquiring the political rights of Macedonia, given to it by the Treaty of Berlin, from which finally developed the so-called Internal Macedonian Revolutionary Organization." For more see: ВМОРО през погледа на нейните основатели. Спомени на Дамян Груев, д-р Христо Татарчев, Иван Хаджиниколов, Антон Димитров, Петър Попарсов. Съст. Т. Петров, Ц. Билярски. София, 2002, с. 203-207;
On the example of the constitution of the Bulgarian Revolutionary Central Committee, they prepared the first constitution of the Macedonian Revolutionary Organization... Its first basic program document was published in 1894 under the name "Constitution of the Bulgarian Macedonian-Odrina Revolutionary Committees", and the Organization, even without even calling it an organization, they called it BMORC for short. Under the official name of BMORC, it existed less than two years after its founding congress. P. Pop Arsov testifies to this in his own way. He is considered the author of the first Constitution. Manol D. Pandevski, Makedonskoto osloboditelno delo vo XIX i XX vek, Tom 1, Misla, 1987, str. 87.
At the second meeting, one of the important points on the agenda was probably the adoption of the constitution... The participants found revolutionary literature from the time of the Bulgarian revolutionary struggles... The drafting of the draft constitution was entrusted to P. Pop Arsov. At subsequent meetings, the six accepted the constitution and this was its first act... There is a printed constitution entitled "Constitution of the Bulgarian Macedonian-Odrina Revolutionary Committees", and which is claimed to be the first constitution of the Internal Organization. Крсте Битовски, Бранко Панов, Македонија во деветнаесеттиот век до Балканските војни (1912-1913), Том 3; Том 5, Институт за национална историја (Скопје, Македонија), 2003, ISBN9989624763, стр. 162-163.
Lambi V. Danailov, Stilian Noĭkov, Natsionalno-osvoboditelnoto dvizhenia v Trakija 1878-1903, Tom 2, Trakiĭski nauchen institut, Izd. na otechestvenia front, 1971, str. 81-82.
Victor Roudometof (2002) Collective Memory, National Identity, and Ethnic Conflict. Greece, Bulgaria, and the Macedonian Question. Bloomsbury Academic, ISBN9780275976484, p. 112.