Robert Leiber

Robert Leiber, S.J. (10 April 1887 – 18 February 1967) was a close advisor to Pope Pius XII, a Jesuit priest from Germany, and Professor for Church History at the Gregorian University in Rome from 1930 to 1960. Leiber was, according to Pius' biographer Susan Zuccotti, "throughout his entire papacy his private secretary and closest advisor".

Before 1924, Leiber worked with Ludwig Pastor on the publication of his 20-volume Papal History. From 1924–29, he was advisor to Eugenio Pacelli while he was Nuncio in Munich and in Berlin. While Professor at the Gregorian, he continued advising Pacelli, who was then Cardinal Secretary of State. After Pacelli was elected to the papacy as Pope Pius XII in 1939, Leiber helped and advised him until the Pope's death on 9 October 1958. Leiber is described as Pie XII's "most trusted aide". However he never was a Vatican official. He was a respected and feared "unofficial official". According to Mark Riebling, known in papal Rome as the "little asthmatic", "some described him with a Latin quip: Timeo non Petrum sed secretarium eius - "I do not fear Peter [the Pope], but his secretary".

He assisted Pius XII in researching the topics for his speeches and radio messages. Leiber was one of an "impromptu band of willing Jesuits" whom Pius XII employed "checking and double-checking every reference" in his written works. Leiber, stationed at the Pontifical Gregorian University, three miles from the Vatican, complained after Pius XII's death that he was often expected to "drop whatever he was doing and hasten to the Vatican", taking public transportation.

As the Pope's trusted Private Secretary, Leiber acted at the intermediary between Pius XII and the German Resistance. He met with Joseph Muller, who visited Rome in 1939 and 1940 to obtain assistance from the Pope in acting as an intermediary between the Resistance and the Allies in the lead up to a planned coup against Hitler. Later in the war, Leiber remained the point of contact for communications from Colonel-General Ludwig Beck in the lead up to the 1944 July Plot.

...
Wikipedia