 According to Hitler biographer John Toland , following the November 1939 assassination attempt by Johann Georg <unk> , Hitler said Pius would have wanted the plot to succeed : " he 's no friend of mine " . In the spring of 1940 , a group of German generals seeking to overthrow Hitler and make peace with the British approached Pope Pius XII , who acted as an interlocutor between the British and the abortive plot . According to Toland , Munich lawyer , Joseph Muller , made a clandestine trip to Rome in October 1939 , met with Pius XII and found him willing to act as intermediary . The Vatican agreed to send a letter outlining the bases for peace with England and the participation of the Pope was used to try to persuade senior German Generals Halder and Brauchitsch to act against Hitler . 
