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
Archduke Franz Ferdinand of Austria of Franz Joseph and Maximilian) and of his second wife, Princess Maria Annunciata of Bourbon-Two Sicilies. In 1875, when he was only eleven years old, his cousin Francis V, Duke of Modena died, naming Franz Ferdinand his heir on condition that he add the name "Este" to his own. Franz Ferdinand thus became one of the wealthiest men in Austria. In 1889, Franz Ferdinand's life changed dramatically. His cousin Crown Prince Rudolf committed suicide at his hunting lodge in Mayerling. This left Franz Ferdinand's father, Karl Ludwig, as first in line to the throne. Karl Ludwig died of typhoid fever