Battle of Cer On 28 June 1914, Bosnian Serb student Gavrilo Princip assassinated Archduke Franz Ferdinand of Austria in Sarajevo. The assassination precipitated the July Crisis, which led Austria-Hungary to issue an ultimatum to Serbia on 23 July on suspicion that the assassination had been planned in Belgrade. The Austro-Hungarian government made the ultimatum intentionally unacceptable to Serbia, and it was indeed rejected. The Austro-Hungarians declared war on Serbia on 28 July and that same day the Serbs destroyed all bridges on the Sava and Danube rivers in order to prevent the Austro-Hungarians from using them during any future invasion. Belgrade was shelled
Trialism in Austria-Hungary 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 ways instead of two, with the Slavic element given representation at the highest levels equivalent to what Austria and Hungary had at the time. Serbians saw this as a threat to their dream of a new state of