There were much political tensions that existed much prior to the World War I. Two groups were formed.
Austria-Hungary decided to attack Bosnia which would make them occupy over Balkans, which was open threat to Serbia. Also this was not accepted by Russia. Russia failed to receive any support from France and Great Britain. Serbia and Russia surrendered.
Following the slaying of Austrian Archduke Franz Ferdinand by a Bosnian Serb terrorist in Sarajevo, triggered an enmity between Austria –Hungary and Serbia which lead to the Gory World War I. Germany lost in the battle and signed the most despised pact.
