To wipe out Serbia altogether Austria blamed it for the terrorist attacks. Even so there was no evidence to attach Serbia to the attacks.
Russia their ally declared war on Austria. Germany tried the same as previously and told Russia to back down but Russia was ready and did not so Germany declared war on Russia. This was the spark in the gigantic bonfire of causes that started the First World War.
Empires and Alliances
Germany had recently become united in to a country from squabbling city-states. Prussia was the largest of these, which in 1870 had won a war against France to gain a territory called Alsace-Lorraine, which was a big industrial area.
Like Italy who had also become a united country recently, Germany wanted to have an empire as great as the United Kingdom you could even go as far to say Germany felt jealous of Britain for having such a great and powerful empire.
Russia so far had no access to the Mediterranean Sea, unless of course it went through the Balkans an area also wanted by the Austrians for the same reason. This is the reason why Russia remained friendly to Serbia who of course was a major power in the Balkans.
As Austria Italy and Germany, all wanted to expand their empires without taking little land from each other it seamed logical to create an alliance together.
Britain had little concern for what happened in Europe, it wanted to concentrate its priorities overseas to its vast empire. Although, it had to sort out a few rivalries. Britain was concerned about France who also had a growing empire in the 19th century; it also had concerns about a powerful empire in the east, Russia. Above all Britain was concerned about Germany and its growing power and want for foreign empires. By the early 20th century, Britain had sorted matters with France by coming to agreements with colonies in North Africa. Russia meanwhile had been beaten in a war with Japan, which weakened them a little.
Britain began to have friendly negotiations with France and Russia. Britain, France and Russia were all worried about growing German power in central Europe as they had just beaten France in a recent war and had stood up to Russia when Austria took over Bosnia. Britain signed an agreement with France in 1904 and Russia in 1907. The Triple Ente was formed.
The arms race
Germany felt surrounded, it was almost sure that the Ente was planning something. It still however planned to increase its empire by building a fleet of ships which was second largest to that of the U.K. Britain wanted to know why Germany had all these ships in the north sea, as it had practically no empire to protect and little land to gain. When the U.K approached the Kaiser, he only said that Germany needed to protect their growing trade. This still did not make Britain feel at ease, they still could not understand the numbers. The race was on, who could build the best and biggest navy. In 1906, Britain built a modern ship called a dreadnought. Germany built her own dreadnoughts; by 1914, Britain had 29 and Germany only 17.
The arms race on land had begun. While Britain and Germany had built up their navies the rest of Europe were building up there armies. Russia was almost backward military wise, but had one of the biggest armies and if given enough time could train it up.
The Germans had a big army that was efficiently trained and ready for battle. Their strategy was to go via Belgium and attack France. Then along side, Austria attack Russia who was thought to be slow in moving their forces this was the Schlieffen plan. Italy however was the weak side to the alliance they did not have a big army and it was not efficiently trained. Britain had a secret weapon. Again, her empire played a big role. She could transport thousands of troops from different parts of her empire at her disposal. She also had an efficient well trained but small number of soldiers who could fight along side France at short notice.
Each army had made sure it was ready for war when it broke out. Every country had its own plan and its own analysis of what the other side was going to do.
Why did the assassination spark WW1?
In 1905, the people of Morocco were in a struggle against there French leaders. Kaiser Wilhelm showed his support for the Moroccan people. France was furious. He wanted to be a major power in Africa. Except he was humiliated, when the people rejected his views and international powers made him back down.
The Kaiser was furious. In 1911, he sent a gunboat to establish a naval base in the territory. Again, he was made to back down.
This was just another event that could have triggered the war, as it was a reason for France to declare war on Germany. Fortunately, it did not. The major powers were only looking for excuses to declare war on each other. The fact of the matter is that this was not the reason they used. Instead, they used the assassination to start the war.
The want to further empires was a major part to play in the causes of the war. Nevertheless, the most important role in the causes of the war was the fact that everyone was preparing for war and NOT! Settling down and discussing with each other how to prevent it.