The first reason why the war occurred was because of Mutual defense alliance. It was one of the main causes of WWI. European countries signed agreements stating they will back one another without doubt in terms of war. Before the war, there were two main alliances. The two alliances were the Triple Entente and the Triple Alliance. The Triple Alliance consisted of Germany, Austria-Hungary, and Italy and the Triple Entente consisted of United Kingdom, France, and Russia. However when the war started, the alliances went to war with one another. Other countries joined in and both alliances grew larger. The Triple Alliance became known as the Central Powers and the Triple Entente became known as the Allied Powers. The Central Powers consisted of Germany, Austria-Hungary, Italy, Bulgaria, and the Ottoman Empire. The Allied Powers consisted of United Kingdom, France, Russia, Serbia, and the United States. When Austria-Hungary attacked Serbia, Russia steps in on behalf of its allied Serbia. Germany seeing Russia joined in, steps in defense of Austria-Hungary and declared war on Russia. From there, countries in both alliances joined in in support of their alliances and agreement signed making the war the war of the world. If it wasn’t for the agreements assigned the war wouldn’t have been a world war.
The second reason why the war occurred was because of Imperialism. According to define imperialism website, imperialism is defined as “the extension of national power, authority, or influence to other countries or regions through policies of direct or indirect control.” This was a growing problem in Europe. Every European country wanted to expand their territory and control. As a result, it created tension between nations and sense of competition. Some saw others as threats and the war was the best excused they had to act on the hatred they had for one another due to expansion of territory. With vast majority of land in Asia and Africa rich in minerals, Europeans saw an opportunity that they couldn’t ever pass on. This was an opportunity that would build up their empires and it led to the world getting in to war to eliminate one another.
The third reason why the war occurred was because of Militarism. Entering the 20th Century, the intense race for arms among the super powers of the world began. According to history on the net website, “The growing European divide had led to an arms race between the main countries. The armies of both France and Germany had more than doubled between 1870 and 1914 and there was fierce competition between Britain and Germany for mastery of the seas. The British had introduced the 'Dreadnought', an effective battleship, in 1906. The Germans soon followed suit introducing their own battleships.” Moreover, Great Britain navy increase significantly in numbers. This increase in militarism among the super powers of the world led to the world going into war.
However, some historians believe that the causes of the war was not because of the death of the Austria-Hungarian archduke, mutual…