The Yugoslav Committee (, , ) was a World War I–era, unelected, ad-hoc committee. It largely consisted of émigré Croat, Slovene, and Bosnian Serb politicians and political activists whose aim was the detachment of Austro-Hungarian lands inhabited by South Slavs and unification of those lands with the Kingdom of Serbia. The group was formally established in 1915 and last met in 1919, shortly after the breakup of Austria-Hungary and the establishment of the Kingdom of Serbs, Croats and Slovenes, which was later renamed Yugoslavia. The Yugoslav Committee was led by its president, the Croat lawyer Ante Trumbić, and, until 1916, by Croat politician Frano Supilo as its vice president.
The members of the Yugoslav Committee had different positions on topics such as the method of unification, the desired system of government, and the constitution of the proposed union state. The bulk of the committee members espoused various forms of Yugoslavism – advocating for either a centralised state or a federation in which lands constituting the new state would preserve a degree of autonomy. The committee was financially supported by donations from the Croatian diaspora, and by the government of the Kingdom of Serbia, led by Nikola Pašić.
Representatives of the Yugoslav Committee and the Serbian government met on the Greek island of Corfu in 1917; they discussed the proposed unification of South Slavs and produced the Corfu Declaration, outlining some elements of the future union's constitution. Further meetings took place at the end of the war in Geneva in 1918. Those discussions resulted in the Geneva Declaration, which described a confederal constitution of the union. The Government of Serbia repudiated the declaration shortly afterwards. The State of Slovenes, Croats and Serbs, which was formed as Austria-Hungary was breaking up, treated the Yugoslav Committee as its representative in international affairs. The committee soon came under pressure to unify with Serbia and proceeded to do so in a manner that ignored the earlier declarations. It ceased to exist shortly afterwards.
Background
The idea of South Slavic political unity predates the creation of Yugoslavia by nearly a century. The concept was first developed in Habsburg Croatia by a group of Croat intellectuals who formed the Illyrian movement in the 19th century. It evolved through many forms and proposals. The Illyrian intellectuals argued that Croatian history is a part of a wider history of the South Slavs, and that Croats, Serbs, and potentially Slovenes and Bulgarians were parts of a single "Illyrian" nation, choosing the name as a neutral term. The movement began as a cultural one, promoting Croatian national identity and integration of all Croatian provinces within the Austrian Empire, usually in reference to the Habsburg kingdoms of Croatia, Slavonia, and Dalmatia, and a part or all of Ottoman Bosnia and Herzegovina. A wider aim was to gather all South Slavs or Jugo-Slaveni for short, in a commonwealth within or outside the Empire. The movement's two directions became known as Croatianism and Yugoslavism respectively, meant to counter Germanisation and Magyarisation.
Fearing the (drive to the east), the Illyrians believed Germanisation and Magyarisation could only be resisted through unity with other Slavs, especially the Serbs. They advocated for the unification of Croatia, Slavonia, and Dalmatia as the Triune Kingdom. The concept was expanded to encompass other South Slavs in Austria or Austria-Hungary after the Compromise of 1867, before aspiring to join other South Slavic polities in a federation or confederation. The proposed consolidation of variously defined Croatian or South Slavic lands led to proposals for trialism in Austria-Hungary, accommodating a South-Slavic polity with a rank equal to the Kingdom of Hungary.
After the neighbouring Kingdom of Serbia achieved independence through the 1878 Treaty of Berlin, the Yugoslav idea became irrelevant in that country. Before the First Balkan War in 1912, Serbia was mono-ethnic and Serbian nationalists sought to include those they considered to be Serbs into the state. It portrayed the work of bishops Josip Juraj Strossmayer and Franjo Rački as a scheme to establish a Greater Croatia. A group of Royal Serbian Army officers known as the Black Hand exerted pressure to expand Serbia; they carried out a May 1903 coup that brought the Karađorđević dynasty to power and then organised nationalist actions in the "unredeemed Serbian provinces", specified as Bosnia, Herzegovina, Montenegro, an Old Serbia – meaning Kosovo – Macedonia, Central Croatia, Slavonia, Syrmia, Vojvodina, and Dalmatia. This echoed Garašanin's 1844 Načertanije, a treatise that anticipated the dissolution of the Ottoman Empire, and which called for the establishment of Greater Serbia to pre-empt Russian or Austrian expansion into the Balkans by unifying all Serbs into a single state.
In the first two decades of the 20th century, Croat, Serb, and Slovene national programmes adopted Yugoslavism in different, conflicting, or mutually exclusive forms. Yugoslavism became a pivotal idea for the establishment of a South Slavic political union. Most Serbs equated the idea with Greater Serbia or a vehicle to bring all Serbs into a single state. For many Croats and Slovenes, Yugoslavism protected them against Austrian and Hungarian challenges to the preservation of their own national identities and political autonomy.
Prelude Florence meeting
In October 1914, Serbian Prime Minister Nikola Pašić learnt the Government of the United Kingdom was considering expanding the alliance against the Central Powers, which at that time consisted of the German Empire and Austria-Hungary. The UK intended to persuade Hungary to secede from Austria-Hungary and to persuade the Kingdom of Italy to abandon its neutrality so both countries could join the alliance of the UK, France, and Russia that was known as the Entente Powers. Pašić discovered the UK was considering guaranteeing Hungarian access to the Adriatic Sea through the Port of Rijeka and overland access to Rijeka over Croatian soil, and resolving the Adriatic Question satisfactorily for Italy. Pašić thought these developments, coupled with a potential UK–Romanian alliance, would threaten Serbia and jeopardise the Serbian objective of gaining access to the Adriatic.
In response, Pašić directed two Bosnian Serb members of the Austro-Hungarian Diet of Bosnia, Nikola Stojanović and Dušan Vasiljević, to contact the émigré Croatian politicians and lawyers Ante Trumbić and Julije Gazzari, in order to resist the pro-Hungarian British proposals and to create a Slavic alternative. Pašić proposed the establishment of a body that would cooperate with the Government of Serbia on the unification of South Slavs in a state that would be created through the expansion of Serbia. The policy of expansion was to be set and controlled entirely by Serbia, and the proposed body would carry out propaganda activities on its behalf. The four men met in Florence, Italy, on 22 November 1914. In January 1915, Frano Supilo, who was once a leading figure in the Croat-Serb Coalition, the ruling political party of the Austro-Hungarian realm of Croatia-Slavonia, met with British foreign secretary Sir Edward Grey and Prime Minister H. H. Asquith, providing them with the manifesto of the nascent Yugoslav Committee and discussing the benefits of South Slavic unification. The manifesto was co-written by Supilo and British political activist and historian Robert Seton-Watson.
Niš Declaration
The Serbian leadership considered World War I to be an opportunity for territorial expansion beyond the Serb-inhabited areas of the Balkans. A committee that was tasked with determining the country's war aims produced a program to establish a single South-Slavic state through the addition of Croatia-Slavonia, the Slovene Lands, Vojvodina, Bosnia and Herzegovina, and Dalmatia. Pašić thought the process should be implemented through the addition of new territories to Serbia. On 7 December, Serbia announced its war aims in the Niš Declaration. The declaration called on South Slavs to struggle to liberate and unify "unliberated brothers", "three tribes of one people" – referring to Serbs, Croats, and Slovenes. This formulation was adopted instead of an explicit goal of territorial expansion as a way to attract support from South Slavs living in Austria-Hungary. The Serbian government wanted to appeal to fellow South Slavs because it feared little material support would be delivered from its Entente Powers allies as it became clear the war would not be short. Serbia assumed a central role in the state-building of the future South Slavic polity, with support from the major Entente Powers.
Supilo initially assumed the Niš Declaration meant Serbia was fully supportive of his ideas on the method of unification. He was convinced otherwise by Russian foreign minister Sergey Sazonov, who informed Supilo that Russia only supported the creation of Greater Serbia. As a result, Supilo and Trumbić did not trust Pašić, and considered him a proponent of Serbian hegemony. Despite the mistrust, Supilo and Trumbić wanted to work with Pašić to further the aim of South-Slavic unification. Pašić offered to work with them towards the establishment of a Serbo-Croat state in which Croats would be given some concessions, an offer they declined. Trumbić was convinced the Serbian leadership thought of unification as a means to conquer neighbouring territories for Serbian gain.
Trumbić and Supilo found another reason to distrust Pašić when Pašić dispatched envoys to address Sazonov's opposition to the addition of Roman Catholic South Slavs to the proposed South Slavic union. The envoys wrote a memorandum claiming Croats only inhabit the north of Central Croatia, and that the regions of Slavonia, Krbava, Lika, Bačka, and Banat should be added to Serbia, as well as the previously claimed Dalmatia, and Bosnia and Herzegovina. Trumbić and Supilo became convinced that because of the Government of Serbia's expansionist policy, the proposed unification would be perceived within Croatian-inhabited areas of Austria-Hungary as a Serbian conquest rather than as a liberation. They decided to proceed with caution, gather political support abroad, and to refrain from the establishment of a Yugoslav Committee until Italy's entry into the war became certain.
Treaty of London
The Entente Powers ultimately concluded an alliance with Italy by offering it large areas of Austria-Hungary that were inhabited by South Slavs, mostly Croats and Slovenes, along the eastern shores of the Adriatic Sea. The offer was formalised as the 1915 Treaty of London, and caused Trumbić and Supilo to reconsider their criticism of Serbian policies. This was because they saw potential Serbian war success against Austria-Hungary as the only realistic safeguard against Italian expansion into the Slovene-and-Croat-inhabited lands. Supilo was convinced Croatia would be partitioned between Italy, Serbia, and Hungary if the Treaty of London was to be implemented.