Why did war break out in Europe in 1939?

When Hitler came to power in Germany in 1933 he promised to reverse the Treaty of Versailles, like many Germans Hitler believed that the treaty of Versailles was unjust and blamed Germany’s problems on the peace settlement. He also hate it so much he called the German leaders who signed it ‘The November criminals ‘this shows his hatred towards the treaty, but this wasn’t the only reason why he dislike the treaty so much, the treaty was a constant remainder to Germans of their loss in First World War and the treaty was also a symbol of Germanys defeat and disgrace that came with it, it humiliated the Germany.
Hitler thought it would be necessary to destroy the Treaty of Versailles in order to further his aims, also when Hitler came to power, reparations had been reduced and eventually cancelled in 1932 but most of the points were still in place.
Hitler’s aims were to change the territorial settlement of Treaty of Versailles by regaining lands which had been taken from Germany at Versailles, including the Saar and Danzig and bring the seven million German-speaking people in Austria, and the four million in Czechoslovakia and Poland, into his empire this again involved destroying the peace settlement of 1919. He also wants to build up his army to prove Germany was still the Great power and to expand in east, probably against communist USSR- Hitler hated Communist. This aim was probably intended for future confirmed as the greatest power in Europe. The first stage of Germans struggle would be to strengthen its lands in Europe. He couldn’t do it alone; Hitler felt the main enemies will be France and USSR, so his aim was to get friendship with Italy and Britain against them.

In the 1930s there were two incidents that really tested the League of Nations.
The Manchurian Crisis was caused when Japan had been dissatisfied with the peace settlement at the end of the First World War, Many thought the answer would be the expansion of Japan into Manchuria; this would make room for growing population and markets for Japanese good. In September 1931 the Japanese claimed that there had been an explosion on railway line at Mukden, which they said was sabotage by the Chinese, there was no certainty that there had been an explosion but this gave an excuse for the Japanese army to invade.
The Japanese army quickly defeated the Chinese at Mukden, they hadn’t got permission from the government but success was so popular in Japan that army was now in control of Japanese policy. China claimed Japan had committed an act of aggression, Japan claimed that it had gone into Manchuria to restore order in the end Japan had done wrong but it had already reorganised Manchuria and called it Manchukuo, and Japan walk out the League.
The Abyssinian Crisis was caused when Italy launch an attack on Abyssinia , it was one of few places Africa which had not been taken by the European countries and it was easy to attack because it was next to Italian colonies of Eritrea and Somaliland . The Italians had tried to do this in 1896 but had been defeated at the battle of Adowa; Mussolini planned gain revenge for this defeat and wants to benefit the Italian economy. Italy, like Japan in 1931, was in permanent member of council of the League. The Manchurian Crisis had given Mussolini the impression that the league would not resist an act of aggression by a major power.
In these sources you can see the League of Nations non-action in Abyssinian Crisis and Manchurian Crisis showed other nations like Germany that the League are powerless and irrelevant, giving Hitler the impression that he can do what he wants because the league didn’t do anything with the other Crisis’s.
In 1936 Hitler began his policy of reclaiming lost German territory and Neville Chamberlain who become prime minister in 1937, he believed in taking an active role in solving Hitler’s grievances , he felt that Germans had good reasons to be upset at many of the terms of the Treaty of Versailles . What he wanted to do was to find what Hitler want and show him that reasonable claims could be met by negotiation instead of by force, so this way the problems of treaty could be solved, Germany could be satisfied and there would be no war, so he made an appeasement and Hitler could get what he wants, little did Chamberlain know of the risks of appeasement.
After 1937 Frances supported appeasement because of the increased of security it had with the building of the Maginot line and Britain already agreed because they didn’t want a war and they felt sorry for Germany because of the treaty. Hitler got what he wants with the appeasement.
In 1939 Hitler made an agreement with Stalin called the Nazi-Soviet pact, the pact was strange because Fascism and communism were sworn enemies and Hitler never hidden his opposition to communism as expressed in Mein the Kampf.
The Nazi-Soviet pact went against the Anti-Comintern pact that Hitler signed with Italy and Japan in 1937, which was in opposed to communism. In the pact the USSR and Germany agreed not interfere against other power in event of war, secret clauses divide Poland between them, the USSR took the land it lost at the end of First World War and Germany receiving the west of Poland including Danzig and the Polish Corridor. This pact benefited both Hitler and Stalin because it meant that Hitler attack on Poland was inevitable and he was prevented two danger of wars on two fronts and in the end they both got bits of Poland.
When Hitler invaded Poland in 1939, Britain and France keep their pledge and on 2 September they declared war on Germany , much to Hitler’s surprise, Britain warned him that it would join the war if Germany invade Poland . THERE WAS NO HOPE OF OTHER Munich. Hitler had gone too far. The collapse of Czechoslovakia in March 1939 proved to be last straw for the appeasers. Public opinion in Britain’s was in favour of opposing Hitler. On 1 septemberb1939 German troops invade Poland. On 3 September Britain declared war on Germany. So that’s how invasion of Poland led to war in Europe, Hitler went too far and Britain was not just going to watch!!!.
Although it was Hitler’s actions which led to war, many other factors were important in making the war happen like the way the League of Nations handled the Manchurian Crisis and Abyssinian Crisis, it gave a green light to dictators and other country which were trying to bend the rules which the league had set. Hitler took advantage of Crisis’s to put his plans forward to reversed the treaty of Versailles and to get Germany out of there depression, make Germans proud again and make there empire powerful again.
There were many other factors that led to war like great depression , it hit USA first and spread like shockwave a cross the world and it was a vicious circle because none of the country could afford to paid its loan or to traded, so no money was coming in and no one was getting paid and there was no money and the people suffered, they just want a way out and Hitler saw a way to get his people out of this by getting out of treaty and getting back his land and others that wasn’t his in first place and by doing this he caused what we know as the second world war.
There are hundreds of reason that led towards the war and some are just the timing but most are the fault of Hitler and his malicious planning , he saw an opportunity and he took it , causing country to turn against country ,friends against friends, father against sons ., causing a war we still haven’t recover from emotionally may never do so