 A significant early point of divergence is that Heydrich survived the assassination attempt by Czech fighters in May 1942 (he was killed in reality) and later became head of the SS.Another significant divergence is the political career of Kennedy, who was, in real life, disgraced in 1940 during the Battle of Britain.In the novel, for an unexplained reason, his political fortunes did not suffer or possibly recovered after the German victory, and he eventually became US President.