Why was archduke franz Ferdinand assassinated and how did Austria-Hungary react?

Answer 1

It was a politically motivated killing. He was killed in Sarajevo, Bosnia- Bosnia is full of Serbian people, and a lot of them wanted to break away from Austria-Hungary and join Serbia (which was a separate kingdom). A lot of Serbs wanted that to happen too; there was a group called "The Black Hand" that tried to help make it happen, and some of its leaders worked for the Serbian government/military.

However, the Empire did not want to give up Bosnia. Franz Ferdinand was actually friendly towards the Bosnians, and wanted to set them up as a kingdom under the emperor, just like Hungary had done in 1867- they would have their own parliament and government, but the emperor would deal with foreign affairs. The reigning emperor, Franz Josef, was against that idea, but he was a very old man and wasn't expected to live much longer.

If Franz Ferdinand became emperor and did this "Ausgleich" (as it was called when Hungary did it) for Bosnia, it would significantly damage support for the Black Hand and their plans. So killing the heir to the imperial throne would not only be a big Propaganda victory for the separatists, but would also eliminate a major political threat to them.

After the assassination was successful (although the assassin, Gavrilo Princip, wasn't technically a member of the Black Hand- he wanted to be a member, but was considered too young and inexperienced), the Austrian government was furious. They knew Serbia was involved (they were aware of the Black Hand), so they made a list of ten demands and sent it to Serbia's government. Despite how harsh the demands were, Serbia accepted all but one (and that one was technically unconstitutional, so Serbia was legally disallowed from accepting).

After Serbia's refusal to accept all of the demands, the major countries began a flurry of diplomatic discourse to try to avoid the war. In the end, one month after the Archduke's assassination, Austria declared war on Serbia, and World War I had officially begun.