was the assassination of Archduke Franz Ferdinand of Austria-Hungary. In June 1914, a Serbian-nationalist terrorist group called the Black Hand sent groups to assassinate the Archduke. Their first attempt failed when a driver avoided a grenade thrown at their car. However, later that day a Serbian nationalist named Gavrilo Princip assassinated him and his wife while they were in Sarajevo, Bosnia which was part of Austria-Hungary. This was in protest to Austria-Hungary having control of this region. Serbia wanted to take over Bosnia and Herzegovina. This assassination led to Austria-Hungary declaring war on Serbia. When Russia began to mobilize due to its alliance with Serbia, Germany declared war on Russia. Thus began the expansion of the war to include all those involved in the mutual defense alliances.