List and explain 3 Causes of the Great War? Some of any causes to a war happen with time. One of the causes of the Great War was Nationalism. Nationalism was a tension created in the world by imperialism, which was strongly linked to nationalism. Many people in each nation of Europe felt themselves to be superior to the peoples of other nations. This convinced leaders of various nations that their country had the right to rule territory beyond their own borders and on different continents. Another cause that happened over time was Militarism. …