Battle of Kolubara their respective commands, and the 5th and 6th armies were merged into a single 5th Army of 95,000 men. 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
Archduke Leopold Ferdinand of Austria Archduke Leopold Ferdinand of Austria Archduke Leopold Ferdinand of Austria (2 December 1868 – 4 July 1935) was the eldest son of Ferdinand IV, Grand Duke of Tuscany, and Alice of Bourbon-Parma. In 1892 and 1893 Leopold accompanied Archduke Franz Ferdinand of Austria on a sea voyage through the Suez Canal and on to India and Australia. The relationship between the two Archdukes was extremely bad and their permanent attempts to outdo and humiliate the other one led the "Kaiser" Franz Joseph to order Leopold Ferdinand to return to Austria immediately. He left the ship in Sydney and went back