However, many other reasons led to this war, some occurring as far back the late 1800's. According to the article above, the author stresses that the nationalism was one of the primary causes of the war. In the ninetieth and twentieth centuries, especially after the French Revolution nationalism was becoming a powerful force in Europe so people that had the same culture, language wanted their own country. And that was the problem for the government of Austria-Hungary that did not want to lose their power and control. The Slavs in the southern part of the empire were their main concern since they wanted to join up to Serbia.
Militarism is the second cause according to the article above, which comes after the nationalism.
To understand what the author means by militarism one should be familiar with the situation of the world in the beginning of the century, which was the result of both industrial and democratic revolutions. Britain at that time was the largest empire in the world, and it also had the largest navy. The navy was so big and strong because the Britons needed to protect their empire and maintain the sea routes between the different colonies. The Kaiser William II of Germany hated and envied Britain for having a stronger navy than his. He increased the German navy and built many warships.