July Ultimatum

The July Ultimatum was a demand issued by Austria-Hungary to the Royal Serbian Government at 6 pm on 23 July 1914, after the Assassination of Archduke Franz Ferdinand of Austria. 
Austria-Hungary's government did not directly accuse Serbia for the assassination but for "doing nothing to suppress" the subversive anti-Austro-Hungarian movement in Serbia which grew beyond Serbia's borders and which was responsible for acts of terrorism, assassination attempts and murders.
Serbia refused to accept one of the ten items of the ultimatum, and so Austria-Hungary mobilized their army. This, along with a chain of Alliances in Europe (Triple Entente and Central Powers) helped cause World War I.
The Ultimatum Requests.
The Ultimatum requested Serbia to pledge itself for the following:
The Russian Memorandum of Advice to Serbia.
The Russia asked Austria-Hungaria to extend the ultimatum deadline which would allow the Governments of the Great Powers to become acquainted with and to investigate the documents on the Sarajevo crime.
The Serbian Response.
The Royal Government binds itself further: