Before doing anything, Austria consulted Germany. They knew Russia supported the
Balkan states. Because of the Triple Alliance agreement, any Austrian action against
Serbia would force Russia into a major war with Germany, or to abandon its loyalty to
Serbia. Assured of their success either way, Germany and Austria-Hungary took a
chance that the Schlieffen Plan would work and that soon they could take their pick
of the European empires and their colonies.
After three weeks, Austria-Hungary replied with an ultimatum to Serbia.
- Serbia to take full responsibility for the murder, though Princip was not Serbian but Bosnian. Austria claimed that the conspirators confessed to the murders being planned with Serbian approval and weapons.
- The right to police 'anti-Austrian' groups within Serbia.
- The right to prosecute these and other conspirators in Austrian courts.
The terms were more severe than Serbia could possibly accept, and Austria-Hungary
must have known this. To allow Austrian police into Serbia would challenge Serbia's
right to rule itself, making it in effect a territory of Austria-Hungary. Serbia
was given only 48 hours to decide on whether to accept the ultimatum. Refusal
certainly meant war.
After seeking Russian advice, Serbia refused to accept the parts of the ultimatum
that allowed Austrian troops or police into Serbia. It asked that other powers
like France and Germany help resolve this disagreement. Austria-Hungary refused
to accept this and declared war.
Meanwhile, Italy declared itself neutral, effectively breaking its treaty
with Germany and Austria-Hungary, but keeping its secret treaty with France.
Italy would be persuaded to join the Allies in 1915 when the Treaty of London
promised them land if they fought for the Allies.
NOTE: The Timeline and the 'Observer' journal might help you with this topic.
It can get very complicated!