Revolutionary Ukrainian Party
The rise of the party came about with a successful consummation after other attempts from various public associations, such as the Brotherhood of Tarasovs and the Social-Democratic Circle of Ivan Steshenko and Lesia Ukrainka, were tried.
The party officially arose at its First Congress in December 1902 when six party communities united into one political party in the following cities: Kharkiv, Poltava, Kiev, Nizhyn, Lubny, and Yekaterinodar, as well as some smaller groups representing such cities as Romny, Pryluky, Odessa, Moscow and Saint Petersburg. The congress, also, elected the party Central Committee, Foreign Committee and Publication Committee, with the last two located abroad in Lemberg and Czernowitz. The Central Committee consisted of Dmytro Antonovych, Yevhen Holitsynsky (later replaced by Volodymyr Vynnychenko), Mykhailo Tkachenko, and V. Kozynenko, while the Foreign Committee was headed by Antonovych and Vynnychenko.
In 1903, the party turned away from its original nationalistic program of an "Independent Ukraine" and changed to a program that was more based on the principals and goals of international social democracy (such as Erfurt Program). That same year RUP was joined by the Kiev-based Ukrainian Socialist Party that mirrored the party programme of the Polish Socialist Party that was created by Kievan Polish students and Polish Ukrainophiles. Also, in 1903, many members of RUP were arrested, while others fled to Lemberg (Lviv). Marian Melenevsky became the head of the Foreign Committee.
In 1904 Mykola Porsh ascended to be a new party leader. The party shifted its focus away from peasantry, instead concentrating on the Ukrainian urban proletariat. In August, a representative of RUP, Yevhen Holitsynsky, participated at the International Socialist Congress in Amsterdam; however, due to a protest by the RSDLP members on a separate Ukrainian delegation he was forced to join their delegation at the event.
In December 1904 the Second Congress of RUP took place which culminated in a split with Marian Melenevsky, leading the more Marxist members to establishing the Ukrainian Social Democratic Union (Spilka) in January 1905, that, later, became an autonomous entity of the RSDLP and was instrumental during the Revolution of 1905 in Ukraine.
In December 1905, RUP was renamed the Ukrainian Social Democratic Labour Party (USDLP).