Serbia suffered more deaths, proportionate to its population, than any other participant in the Great War. For a while, it had even looked as though the state itself would be obliterated. But the tide of war turned dramatically and, in 1918, the dreamed-of South Slav state finally came to pass: the Kingdom of Serbs, Croats, and Slovenes.
But it was far from harmonious. Even after early conflicts in border areas had been resolved, tensions remained. For non-Serbs (many of whom had fought for the Habsburgs), the new state was all too transparently a kind of Greater Serbia: its king was the Serbian king; its capital, Belgrade; its parliament, the Serbian parliament — the Skupština. Even the currency — the dinar — had been that of Serbia.
The Croatian Peasants' Party (HSS) demanded greater autonomy — but its highly popular leader, Stjepan Radić, was assassinated in 1928. The resultant instability caused the king to end democracy and proclaim a royal dictatorship in January 1929. He also renamed the country 'Yugoslavia' — underscoring its unitary status.
Unitary it may have been; united, it certainly was not. How long could the edifice be held together?