World War One had many causes, which can be split up into both long tem and short term. There were three long term causes,

The arms race was a very important long term cause of World War One. 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. When Germany announced their intention t build a powerful German navy Britain became threatened, although they had a bigger navy it was spread across the world. Britain did not think that Germany needed a Navy but of course Germany disagreed. Due to this disagreement Britain introduced the HMS Dreadnought, an effective battleship, in 1906. Germany Quickly followed suit by releasing their own kind of dreadnaught, both nations spent millions on their own navy. Both nations thought the other was only building their navy readying themselves for an attack, and continued to further increase their navy. All the major powers were increasing their armies and Germany in particular glorified war and militarism. The arms race was a particularly significant cause to World War One as the shipbuilding  rivalry, and that all the six power nations were building up their armies, was part of a general movement in the direction of war.

Another long term cause was Empires. The Austria-Hungary empire was beginning to fragment , Austria-Hungary had also had trouble with Serbia which had Managed to break free form the Austria-Hungary empire. Britain and France had already claimed a huge amount of land for themselves making their empires the biggest in the world. However Germany had entered the scramble to acquire colonies too late and had only managed to claim a few areas of Africa for itself. Both Germany and Italy wanted overseas colonies, this was one of their reasons for joining the Triple Alliance. Britain had been threatened by the idea of Germany acquiring a larger empire and this increase the tension between the already hostile alliances. Russia  was also threatened by the idea of Germany increasing the size of it’s empire, Russia thought that to achieve a bigger empire, Germany would take land from Russia. This led to World War One as it increased mistrust  and angered the Germans, they envied Britain and France and thought of them as threats.

The short term cause was the assassination of Archduke Franz Ferdinand of Austria-Hungary, heir to the throne. Franz Ferdinand and his wife were assassinated on the 28th June 1914, in Sarajevo by Bosnian revolutionary, Gavrilo Princip. The Archduke was assassinated for the political objective that the south-Slav provinces could be combined with greater Serbia. This caused The First World War  because Austria-Hungary argued that it was the Serbian Governments plot to assassinate their heir to the throne. War broke out between Austria-Hungary and Serbia, however Serbia had ties with Russia and Russia immediately joined to help defend Serbia. The promise of The Triple Alliance meant that Germany was obliged to help Austria-Hungary , so entered the War. France and Britain then entered the war to help protect Russia.

In conclusion, there were many causes for the Great War which could be split into long term cause and short term causes. The Arms Race was linked in with the empires as ships which were built for the arms race, were built to defend the empires. Empires could also be linked to the alliances, this is because the alliances were made to help nations  gain a larger empire. The arms race can be linked with the alliances, as it was the threat of Germany increasing it’s navy and empire that made Russia and Britain allies. The assassination can be linked with the empires because if it weren’t for Austria-Hungary’s trouble empire the Archduke would not have been assassinated. The most important cause of World War One was the arms race. This is because the arms race increased hostility and clearly made each alliance feel threatened by the other, also without the arms race there would not be enough ships or troops to fight the war.