Explanation: The assassination of Archduke Archduke Ferdinand on June 28, 1914 in Sarajevo is the culmination of hostility between Austria and Serbia, which lasted for decades. Austria saw its chance to expand its influence in the Balkans in the gradual withdrawal of the Turks from the Balkans. On the other hand, the Slavs who lived in Bosnia saw their chance to gain full independence, and saw Serbia as a transitional solution, since Serbia was an independent state, recognized by the West since the Berlin Congress in 1878. At the same time, there was a growing awareness of freedom and independence, as well as national states among the entities that lived within the great Empires, as well as the great powers to recompile their influence. After the assassination in Sarajevo, Austria saw the opportunity to achieve its interest in war against Serbia. For this, it sought support from Germany, from which it received a blank check that whatever it decides against Serbia will have German support. Austria Hungary announced the war on Serbia on July 28, 1914, after which Russia stood on the side of Serbia and entered the war. Then, gradually, the great powers announced the war to Germany, seeing the danger of spreading the German influence.
