The Holocaust started from January 30, 1933 when Adolf Hitler became chancellor of Germany to May 8, 1945 when the war in Europe (World War 2) ended.____ No, those are th … e dates of the Nazi period in Germany. A few mavericks and cranks denied the Holocaust in the 1960s but gained little attention. Holocaust denial on a large scale started in the 1970s. It went hand in hand with claims that Zionists had exaggerated the Holocaust in order to win sympathy internationally for the creation of the state of Israel in 1948.