Map of World with Participants in World War I :
Allies- in green
Central Powers- in orange
Neutral- in grey
The triggering event cause of World War I was the assassination of Archduke Franz Ferdinand, heir to the Austro-Hungarian throne, in 1914. The fact that the assassination did not lead to a war of two nations, but a war among many nations around the whole world, has to do with the alliance system in the era. Although the actual causes of the war are complicated, the escalation of the size of the war can be partly attributed to the alliance treaties.
For the readers’ convenience, some of the entrances of the participants will be listed below:
1. Austria-Hungary- declared war on Serbia due to the assassination.
2. Serbia- became a participant by Austria-Hungary’s war declaration.
3. Russia- allied to Serbia by their treaty
4. Germany- allied to Austria-Hungary by their treaty
5. France- allied to Russia
6. Britain- allied to France. Since Britain has entered the war, her many colonies have became participants, whether with direct military support or financial support.
7. Australia, Canada, India, New Zealand, and the Union of South Africa- entered the war because of their ties with Britain
8. Japan- entered the war due to its treaty with Britain.
As we can see, over 10 additional nations were involved because of their alliance treaties with other nations. Although some nations have entered the war with reasons of their own, it is undeniable that the alliance treaties were strong factors for the escalation of the war to a world-wide scale.
I think the alliance system in Europe was the catalyst that drove the world powers into war. Where the war would’ve been between two nations (Austria-Hungary and Serbia) because of the assassination of Ferdinand by Serbian Nationalists, the treaties between these two nations with other nations went in to effect, prompting other nations to get involved in the war just by treaty.
As succinctly displayed in the post,when Austria-Hungary declared war with Serbia, it prompted Russia to get involved in the war. Then Germany, allied with Austria, sends ultimatum to Russia to halt it’s military preparation. Then Germany declares war against Russia, then later on France, which was allied with Great Britain. All of a sudden, all the major powers of Europe became involved in a war that would last four years and cost millions of lives.
WORLD WAR I – A FAMILY AFFAIR?
Another perspective and perhaps the reason for the tangled web of alliances in Europe preceding the World War I suggests the fact that most reigning houses in Europe were related to each other. That is the monarchs of major countries in the WWI, the King of Great Britain, George V, the Russian Emperor Nicolai II and the German Kaiser, were all first cousins. “If their grandmother Queen Victoria had still been alive, said the Kaiser, she would never have allowed them to go to war with each other” (source: http://www.bbc.co.uk/history/british/britain_wwone/cousins_at_war_01.shtml). “…Edward VII (King of Great Britain), was the German Kaiser’s uncle and, via his wife’s sister, uncle of the Russian Tsar as well. His niece, Alexandra, was the Tsar’s wife. Edward’s daughter, Maud, was the Norwegian Queen, and his niece, Ena, Queen of Spain; Marie, a further niece, was to become Queen of Romania.” http://www.firstworldwar.com/origins/causes.htm).
It is hard to say what role did this kinship play in the WWI. Apparently it did not stop relatives to go against each other with war, while it certainly contributed to the complexity of relationships between countries (including the “tangled web of alliances” itself), which is listed as one important cause of the war. As to the question of how the relatives became enemies, especially, given the fact that many of them were maintaining family ties, it is considered that generals, politicians, diplomats, arms manufacturers and timetables of mobilization overrode the family concerns of the monarchs.
Based on:
http://www.bbc.co.uk/history/british/britain_wwone/cousins_at_war_01.shtml
http://www.firstworldwar.com/origins/causes.htm
http://www.youtube.com/watch?v=AOvB1e4t9jg&feature=related