July 28th 1914
28 July 1914 - Austria-Hungary declares war on Serbia 6 August 1914 - Austria-Hungary declares war on Russia 23 Maj 1915 - Italy declares war on Austria-Hungary
Austria-Hungary declares war on Serbia.
Because that is how a war usually starts- one side declares war on the other.
Austria-Hungary
Serbia
Serbia was in WWI because Austria-Hungary declared war on them.
Serbia Serbia
The 1st country to declare war on Serbia was Austria-Hungary.
After the Austro-Hungary monarchy declared war on Serbia, France and Russia who were protecting Serbia declared war on Austria-Hungary. and then Germany declared war on Russia and France, then UK declared war on Germany...
They went to war with Russia since Russia wanted to help Serbia since they were allies.
Austria-Hungary on Serbia.
Serbia