The First World War was the first world-scale imperialist war carried out by imperialist countries in Eurasia and Africa for the redistribution of colonies and the conquest of world hegemony, with the two opposing military groups of the Allied States with Britain, France and Russia at the core and the Allies with Germany and Austria at the core.

Since the 20th century, the Austro-Hungarian Empire has annexed Bosnia by force and sought to incorporate neighboring Bosnia and Serbia into the Empire¡¯s map, and Serbian nationalists have long been furious about this.On 28 June 1914, the Austrian Emperor Franz Ferdinand and his family, accompanied by the Governor and the Mayor, headed to the municipality of the capital, Sarajevo, following a military exercise on the Bosnian border.

When the team drove on a bridge in the center of the listing, a member of the Youth Bosnia dropped a ground bomb on the car of the Fidynan couple, but without success, the bomb wounded the accompanying in a car behind the Fidynan. After the Mayor's welcome ceremony, Fidynan decided to visit the wounded, on the way was attacked by a member of the Youth Bosnia buried nearby, the first shot in the throat of the Emperor, the second shot in the belly of the Queen. The car immediately returned to the Governorate, but the Emperor's couple broke the air on the way. This is the famous "Sarajevo" incident in history.

The assassination of the Austro-Hungarian Emperor and Emperor Joseph I found an excuse for the Austro-Hungarian Empire to invade Serbia. The Austro-Hungarian Emperor Franz Joseph I canceled his routine visit and wrote a private letter sent on July 5 by the Special Envoy of the Ministry of Foreign Affairs of the Empire to Emperor William II, an ally of the German Empire, to explore German trends. Joseph I knew that Russia would not be willing to give up its interests in the Balkans, and that Russia and Britain had agreed that if the Austro-Hungarian Empire invaded Serbia, Britain and France would face interference. Therefore, the Austro-Hungarian Empire must obtain German support in order to declare war on Serbia.

In fact, Germany had long sought to defeat and weaken its opponents Britain and France in order to dominate Europe. The Sarajevo event made the German Emperor unexpectedly happy, and after receiving a private letter from the Austrian Emperor, he encouraged the Austrian Emperor not to mourn, and firmly assured Germany that it would help one arm. So on July 23, the Austro-Hungarian Empire issued a final ultimatum to the Serbian government, putting out 10 harsh conditions, limiting Serbia to respond within 48 hours. One of which unreasonably asked Serbia to allow Austrian members to trial the murderers of the Sarajevo incident. This was no different from interference in Serbian internal affairs. Besides this, Serbia accepted all of its remaining conditions.

On August 1, Germany declared war on Russia. On the same day, France ordered a general mobilization. On August 3, Germany declared war on France, on August 4, Germany attacked Belgium. On the same day, Britain joined the Alliance and declared war on Germany with the pretext of German destruction of Belgium's neutrality. On August 6, Austria-Hungary declared war on Russia.

Thus, with the ¡°Sarajevo incident¡± as the guiding line, the First World War broke out between the two major imperialist groups of the Allies and the Allied Coalition to compete for commodity markets and redistribute the world.