Hitler was born in Austria in 1889. He developed his political ideas in Vienna, a city with a large Jewish community, where he lived from 1907 to 1913. In those days, Vienna had a mayor who was very anti-Jewish, and hatred of Jews was very common in the city.
During the First World War (1914-1918), Hitler was a soldier in the German army. At the end of the war he, and many other German soldiers like him, could not get over the defeat of the German Empire. The German army command spread the myth that the army had not lost the war on the battlefield, but because they had been betrayed. By a ‘stab in the back’, as it was called at the time. Hitler bought into the myth: Jews and communists had betrayed the country and brought a left-wing government to power that had wanted to throw in the towel.