There were many causes of WWI including assassination, imperialism, militarism, and alliance system, but the initial cause of WWI was nationalism. Nationalism is when one nation believes their nation is superior to another and wants to control other nations. The other causes of the war are influenced by nationalism. Assassination, for example, is when an important official is murdered during a surprise attack for political or religious reasons. Prior to WWI, Franz Ferdinand, the Archduke of Austria-Hungary, was assassinated and created a chain reaction of events to follow. Imperialism played a vital role in causing the war as well. Similar to nationalism, imperialism is when one country introduces power into another country to take advantages.