28th July, 1914
Austria Hungary declared war on Serbia.
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...
Serbia was in WWI because Austria-Hungary declared war on them.
Serbia Serbia
Austria-Hungary declared war on Serbia at the start of World War I.
Austria-Hungary, declared war on Serbia
Serbia
Russia
Austro-Hungarian Archduke Franz Ferdinand was assinated by Serbian nationalists. Austria declared war on Serbia. Russia, allied with Serbia, declared war on Austria, Germany declared war on Russia, England and France declared war on Both.
No, they are allies for ages.
The 1st country to declare war on Serbia was Austria-Hungary.
Mobilized its military because of its alliance with Serbia.