Kingdom of Serbs, Croats, and Slovenes in the context of "Banat, Bačka and Baranja"

The Hungarian Republic (Hungarian: Magyar Köztársaság) was a short-lived republic that existed between August 1919 and February 1920 in the central and western portions of the former First Hungarian Republic (controlling most of today's Hungary and parts of present-day Austria, Slovakia and Slovenia). The state was established in the aftermath of the Hungarian–Romanian War by counter-revolutionary forces who sought to return to the status quo prior to 31 October 1918.

Following this period, the Allies of World War I severely pressured the Hungarians into retreating behind post-war demarcation lines as a provision to the Paris Peace Conference of 1919, which was the Allies' attempt to establish new nation states among the former kingdom's non-Hungarian citizens, the principal beneficiaries of which were the Kingdom of Romania, the Kingdom of Serbs, Croats, and Slovenes, the Austrian Republic, and the Czechoslovak Republic. Subsequently, the Republic was transformed back into the Kingdom of Hungary, which signed the Treaty of Trianon under protest.

The Treaty of London (Italian: Trattato di Londra; Russian: Лондонский договор, romanized: Londonskiy dogovor) or the Pact of London (Patto di Londra, French: Pacte de Londres) was a secret agreement concluded on 26 April 1915 by the United Kingdom, France, and Russia on the one part, and Italy on the other, in order to entice the latter to enter the Great War on the side of the Triple Entente. The agreement involved promises of Italian territorial expansion against Austria-Hungary, the Ottoman Empire and in Africa where it was promised enlargement of its colonies. The Entente countries hoped to force the Central Powers – particularly Germany and Austria-Hungary – to divert some of their forces away from existing battlefields. The Entente also hoped that Romania and Bulgaria would be encouraged to join them after Italy did the same.

In May 1915, Italy declared war on Austria-Hungary but waited a year before declaring war on Germany, leading France and the UK to resent the delay. At the Paris Peace Conference after the war, the United States of America applied pressure to void the treaty as contrary to the principle of self-determination. A new agreement produced at the conference reduced the territorial gains promised by the treaty: Italy received Trentino-Alto Adige/Südtirol and the Julian March in addition to the occupation of the city of Vlorë and the Dodecanese Islands. Italy was compelled to settle its eastern border with the new Kingdom of Serbs, Croats, and Slovenes through the bilateral Treaty of Rapallo. Italy thus received Istria and the city of Zadar as an enclave in Dalmatia, along with several islands along the eastern Adriatic Sea shore. The Entente went back on its promises to provide Italy with expanded colonies and a part of Asia Minor.

The Albanian Republic (Albanian: Republika Shqiptare) was the official name of Albania as enshrined in the Constitution of 1925. Albania came into an alliance with the Kingdom of Italy after signing the Treaties of Tirana, which gave Italy a monopoly on shipping and trade concessions. Albania was declared a constitutional monarchy in 1928. Upon its inception, Italy demanded to be allies with the republic. This was done largely to increase Italy's influence in the Balkans, and to aid Italian and Albanian security in their territorial feuds with the Second Hellenic Republic and the Kingdom of Serbs, Croats, and Slovenes.