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
Prince Lorenz of Belgium, Archduke of Austria-Este to male primogeniture by declaration of Emperor Franz Joseph I of Austria on 31 October 1914 (following the assassination of Archduke Franz Ferdinand of Austria-Este) and was confirmed by Imperial Austrian letters patent, both of which conferred it (with the traditional coat-of-arms of the House of Austria-Este) upon Lorenz's father, Archduke Robert, on 16 April 1917, and has been confirmed for Lorenz by specific reference in Article IX.1 of the constitution of the Kingdom of Belgium. The "Este" suffix descended by male primogeniture and is borne by Lorenz and his successors as heads of the Austria-Este cadet branch of the