10. Russian Growth
9. German Paranoia
8. Arms Race in Europea
7. Decline of the Ottoman Empire
6. Imperialism
Prior to World War I, the major European powers massive head start over Germany in terms of extending their colonies. The resources and raw materials that new colonies could provide were lucrative. For that reason, all these big powers were trying to make the most out of unrest in Europe, leading to more conflict between themselves.
5. Balkan Wars
4. Nationalism
In an attempt to make the most out of instability in the Slavic region, the Slavic people in Bosnia and Herzegovina decided it was the right time to separate from Austria-Hungary and merge into Serbia. Despite the volatile situation in the region, a war that would soon involve all major European superpowers was still only a distant fear for many. This event triggered a series of offenses that significantly narrowed any chance of a peaceful armistice. Nationalism played a role in leading to the war not only in the Balkan region, but across the whole of Europe. The entire region was high on the concept of nationalism, each nation calling itself an “inviolable territory,” So when Germany captured Alsace-Lorraine in 1871, it did not go down very well with the French. When the Slavic region opened up due to repeated conflicts, the newly formed Balkan nations were ready for war if any other European nation tried to annex them into new colonies.
3. Mutual Defense Alliances
As the relationships between nations started to take an ugly turn, countries across Europe began to sign mutual defense agreements with nations they could depend on in the face of war. Since these were mutual defense treaties, it meant that if an allied nation became involved in any sort of war, the other nations had to participate as well in defense of their ally. Prior to the Great War, Russia and Serbia already had an alliance, as did Germany, Austria and Hungary. So it was no big surprise when Russia and Germany also became involved in the conflict between Serbia and Austria-Hungary. But then again, both Russia and Germany had further alliances with other European nations too, increasing the roster of participants in a conflict which eventually became a fully fledged war.
2. Lack of International Laws
These days there are many rules to ensure that nations remain united in international peace, with consequences and ramifications if nations do not abide by them (though their effectiveness is fairly questionable). Back when World War I was on the brink of creating chaos and disarray across the whole of Europe, there were no such laws to keep aggression between nations in check, let alone bring justice to those who annexed territories in the name of their imperial aspirations. Although a global-level economy had already surfaced by the late 19th century, the global community as a whole was yet to devise a system of international law that could restrain one nation from using violence against another. Institutions that were supposed to promote peace were fairly dysfunctional and had little impact on the then international community.
1. Assassination of Archduke Franz Ferdinand of Austria
At a time when many events had brought the now imminent war to boiling point, it was this incident that almost immediately turned much of Europe into an active war zone. The conflict between Austria-Hungary and Serbia over Bosnia’s desire to become part of Serbia was intense. Archduke Franz Ferdinand of Austria was making a visit to Sarajevo with his wife on June 28, 1914. Although the couple narrowly escaped an attack by a Serbian terrorist group called the Black Hand, they were later assassinated on the same day by a Serbian nationalist named Gavrilo Princip while they were still in Sarajevo. Since Princip and his accomplices were Bosnian Serbs, Austria-Hungary accused Serbia of masterminding the assassination and immediately declared war on Serbia. Being in alliance with Serbia, Russia soon mobilized its army in Serbian defense, which in turn led to Germany declaring war on Russia.
-> This is the most directly of all reasons have caused the Great War.
