What triggered Adolf Hitler's rise to power as noted in the nonfiction book, War in Val D'Orcia, 1943-1944?

Germany as a nation had a centuries-long history of seeking, and acquiring, power. Its defeat in World War I, perceived in Germany as a humiliation, was the trigger for the rise to power of Fascist/Nazi dictator Adolf Hitler who aligned with Mussolini to become the primary European members of the Fascist Axis.