Bulgaria during World War I 28 June 1914, Gavrilo Princip, a Bosnian-Serb student and member of Young Bosnia, assassinated the heir to the Austro-Hungarian throne, the Archduke Franz Ferdinand of Austria in Sarajevo, Bosnia. This began a period of diplomatic manoeuvring between Austria-Hungary, Germany, Russia, France and Britain called the July Crisis. Wanting to end Serbian interference in Bosnia conclusively, Austria-Hungary delivered the July Ultimatum to Serbia, a series of ten demands that were intentionally meant to be unacceptable in order to precipitate a war with Serbia. When Serbia acceded to only eight of the ten demands levied against it in the ultimatum, Austria-Hungary declared
Trialism in Austria-Hungary and Serbs. The curiosity is that no act of Sabor dethroned king Karl I, nor did it acknowledge the entering in a state union with Serbia, which is today mentioned in the preamble of the Constitution of Croatia. Trialism in Austria-Hungary In the history of the Austria-Hungary trialism was the political movement that aimed to reorganize the bipartite Empire into a tripartite one, creating a Croatian state equal in status to Austria and Hungary. Franz Ferdinand promoted trialism before his assassination in 1914 to prevent the Empire from being ripped apart by Slavic dissent. The Empire would be restructured three