The complete opening of the Vatican archive concerning the pontificate of Pius XII is of great importance that has been underestimated both in Catholic and public environments. It is a very positive and an important encouragement for the opening of the archives of other popes. .In fact, Pius XII was a very centralizing man and by definition a very “diplomatic” pope. All issues depends on him, directly or indirectly, it is also known that he also filled the role of Secretary of State (Cardinal Maglione had a minor role and only until August 1944 when he died). Moreover, his pontificate was during an absolutely extraordinary period in the presence of a more complex and general war than that of ’15 -’18, with very strong new ideological components (nazism, communism). The understanding and interpretations of the decisions of that time by Pope Pacelli still affect our politics and culture especially for the question as to his attitude towards the Holocaust on which the debate and the search continues forever.