Any empire becomes nervous when another empire is established, especially when the new empire borders its own.
This is doubly true when some components of the new empire were formerly part of the old one.
Austria-Hungary, Mentenegro, and Serbia
Serbia partially accepted the ultimatum from Austria-Hungary but rejected some of the demands. This led to Austria-Hungary declaring war on Serbia, which ultimately sparked the beginning of World War I.
Austria-Hungary's future king was assassinated.
Serbia
Serbia
Austria-Hungary
they promised to support Austria-Hungary after it threatened to invade Serbia
Germany guaranteed Austria-Hungary its support in the conflict with Serbia.
they promised to support Austria-Hungary after it threatened to invade Serbia
Answer this question… Russia had an alliance with Serbia, and Germany had an alliance with Austria-Hungary.
Austria-Hungary did not directly give anything to Serbia during World War I; rather, the conflict was sparked by tensions between the two nations. The assassination of Archduke Franz Ferdinand of Austria in June 1914 by a Bosnian Serb nationalist led Austria-Hungary to issue an ultimatum to Serbia. When Serbia's response was deemed unsatisfactory, Austria-Hungary declared war on Serbia, initiating the larger conflict of World War I.
Austria-Hungary feared Serbia because of the growing size of Serbia and because of Serbia existing as a free national state Hope this helps!