Before the First World War, the Balkans had long been torn apart by inter-state antagonisms and local wars.
The assassination of the nameless Crown Prince of Austria-Hungary in June 1914 was only the trigger of the world war.
In the years leading up to World War I, the European powers had split into two opposing political blocs, in large part because each country had reason to believe that its neighbors might pose a threat to itself.
At that time, Serbia in the Balkans had very close relations with Tsarist Russia, but it was regarded as a thorn in the side of the Austro-Hungarian Empire, which made it difficult for Tsarist Russia and Austria-Hungary to agree on the conflict in the Balkans, and both sides were full of anxiety because of this hidden danger.
Fearing that the French would retake the provinces of Alsace and Lorraine, which they had ceded to them in the Franco-Prussian War (1870-1871), germany had tried to maintain friendly relations with Britain at some point.
But the friendship between the two countries deteriorated after Kaiser Wilhelm II ascended the throne in 1888 , who began to build large warships, no doubt challenging Britain's long-standing maritime supremacy , and Britain's rapid industrialization and search for overseas colonies.