Have you ever wondered what the causes of World War I are? World War I was one of the hardest wars that we have had. There have been different opinions of what those causes are, but I have three facts. The first cause was militarism. The second cause was the Alliance system. The last cause was Imperialism. The causes of World War I are Militarism, Alliance, and Imperialism. Militarism is the competition to have the most military power. Militarism is an important factor in the cause of World War I because Britain had a great navy and Germany wanted a great navy. In fact, Germany and France both wanted the largest army. There is a major emphasis on military power. The alliance system is also in important factor in the cause of World War