No country is doing very well out of the war but Serbia is having a worse time of it than most. The Central Powers have overrun the country and driven the Serbian government into exile. Occupied Serbia is now a land of famine and pestilence.
Yet the Serbian government in exile, now based on Corfu, is still looking forward to the post-war future. Serb nationalists have long dreamed of uniting all Serbs into single kingdom; this after all was what motivated Gavrilo Princip when he shot Austria-Hungary’s Archduke Franz Ferdinand. Up to now the great power patron of the Greater Serbia project was Russia. With Russia now succumbing to revolutionary chaos, Serbian leaders are having to fine-tune their plans for the post-war settlement.
Some politicians from the other Slavic peoples of southern Austria-Hungary went into exile at the start of the war and began to agitate for the formation of a new country for all the southern Slavs, to be called Yugoslavia. Their aims were antithetical to those of the Serbs, as they want a federal country in which the separate Slavic peoples will enjoy equality while the Serbs want a unified Greater Serbia. But the Yugoslavs fear Italian plans for expansion on the Dalmatian coast and want to use the Serbian army as a counter-weight. The Serbs meanwhile are willing to make concessions now that their Russian patron is no longer able to fight their corner.
So it is that today that Nikola Pašić, exiled prime minster of Serbia, and Ante Trumbić of the Yugoslav Committee issue the Corfu Declaration, proposing to establish a Kingdom of Serbs, Croats and Slovenes (with the existing King of Serbia becoming the King of the Yugoslavs).
Britain and France are supportive of this new endeavour, but Italian politicians regard it with immediate suspicion. They had entered the war with dreams of establishing an empire on the eastern shores of the Adriatic. Perhaps if Italian armies had spent the last few years winning a string of impressive victories then Italian politicians would be better able to press their claims, but alas, successive failures on the Isonzo have made Allied leaders less receptive to Italian demands.
Page one of the declaration (Wikipedia)