Nationalistic tensions in Austria-Hungary led to rebellion and the assassination of prominent individuals. The empire was full of many nationalities whose traditions, cultures, and aspirations differed. Therefore, the leadership of Austria-Hungary was unable to satisfy the grievances of many citizens, particularly minorities. Instead of calling for secession from the empire, the leaders of minority groups increased agitation and rebellion against the empire.
Such events perturbed Austrian leaders, who decided to fight against any country that supported the rebels. Countries like Serbia fought back by supporting a terrorist who assassinated the heir to the throne of Austria-Hungary in 1914. The incident sparked more tension until other countries in Europe became part of the conflict, thus starting World War I.