Many classical realists came from a diverse range of intellectual backgrounds, were often originally from Central Europe, and only turned their academic interests to International Relations once they had crossed the Atlantic. This includes scholars, who had left already before fascists were elected into governments across Europe, but most were forced into emigration after the Nazis came to power in Germany in 1933 because of their religious beliefs and/or political standpoints. This chapter reflects on the specific role Europe played in the development of their realist international political thought by investigating the influence of their forced migration, the Holocaust, and the rise of totalitarianism, while not forgetting the role American interlocutors played in formulating their thought