While there was a chain of events that directly led to the fighting, the actual root causes are much deeper. The Causes of World War One were Alliances, Imperialism, Militarism, and Nationalism. I will be going into the detail of these matters to explain the events that triggered the World War.
Countries throughout Europe made defence agreements that would pull them into battle, meaning, if one country was attacked, allied countries were bound to defend them. This was called Alliances. At the start of World War One, Germany and Austria-Hungary allied and became the Triple Alliance or Central Powers Alliance, when Italy joined in 1882. Fearful of that Alliance; in 1894, France made an alliance with Russia, and In 1904 France also made an agreement with Britain called the Entente: not a formal alliance, but a promise to work together. In 1907, Britain made an entente with Russia, forming the Triple Entente (France, Russia, and Britain). Unfortunately, back then, the Governments and Politicians thought that the build-up of armed forces or alliances would keep the peace by acting as a warning to any nation thinking of attacking them, but nowadays we know different.
Alliances helped cause World War One because The Triple Entente alarmed Germany, and she felt surrounded by the alliance; this made a worried, uneasy atmosphere. For example, when Britain joined The Triple Entente and France and Russia formed an alliance (against Germany), she was fearful and wanted to be ready for an attack, so Germany started building up her Empire and Navy. I think this is a valid reason for triggering World War One because each country wanted to be one step ahead of the other, and there is always an end to that, in this case- war. Militarism and Alliances are linked because when Germany built up her Empire and Navy, she also developed her Militarism.
Another cause was Imperialism. European nations ruled smaller countries called colonies, and competed with each other to collect more colonies, gathering colonies became known as Imperialism. Both France and Britain had many colonies in Africa and Asia; then Germany decided she wanted a colonial empire too.
Imperialism helped cause World War One because Germany was jealous of the countries that had other places where they could gather raw materials and cheap labour. Because of Germany building her Empire so quickly, Britain got worried about power and improved their Empire as well. A benefit of Germany's fast increasing Empire, was that most countries thought they were to win, so made an alliance with them. For example, Italy had no part in the war, but when they saw Germany's rising Empire, she thought they were bound to win; she only joined the Alliance to be a part of winning the war.
I think this affected the build-up to World War One because each country wanted more than the other, and in the end, the most likely thing that would happen, is that Britain and Germany wanted the same country, and would end up in a fight or, war. Imperialism is linked to militarism because militarism creates the weapons used to conquer new territory.
Militarism was a cause of World War One because increased military rivalry led not only to the belief that war was coming and when Britain made the HMS Dreadnought in 1906, Germany made a similar battle ship, increasing tension and nerves. For example, colonial rivalry had led to a naval arms race between Britain and Germany; this had worsened relations between both countries. This rivalry no doubt turned to jealously and possibly hate, making it a prime time to start a war. I think that this is a good reason to start war because the competition between the powers led to a building up of weapons and an increase in distrust. Militarism is linked to Nationalism because each country were nationalist about themselves and thought that they were superior, and therefore should have a better army.
Nationalism is a cause of World War One because a nationalist Serbian terrorist group called the Black Hand assassinated the arch duke Franz Ferdinand 28th June 1914.
The Serbians only assassinated the heir to the Austro-Hungarian's because they had recently made an alliance with the Russians, they were feeling very secure and confident, but Austria, having a strong alliance with Germany, declared war.
Russia began to mobilize due to its alliance with Serbia, Germany declared war on Russia. Thus began the expansion of the war to include all those involved in the mutual defence alliances.
Conclusively, I think the main cause of World War One was Alliances because after the assassination of the arch duke Franz Ferdinand, Austria/Hungry declared war, because of the alliances; other countries were tied into the war. An example of an alliance today is France and Britain. This caused the war because they should have felt secure and safe with an alliance, but as we know today, it just made the tension rise- especially when enemies made alliances. Most had backup and were confident to start a war.