Keywords: Benedict XV; Roman Curia; First World War.
The ecclesiastical formation of Giacomo Della Chiesa took place mainly within the Curia of Leo XIII, that is to say in an exceptional phase for the central government of the Church, deprived of temporal power from 1870. Della Chiesa became the witness and the protagonist of the profound transformation that the Roman Curia saw in these circumstances, when men and strategies alternated. Thus it was with the wealth of experience gained in these years that from 1914, as Pope Benedict XV, he had to face the crisis of the Great War. The historical perspective allows us today to gather the consistency of the decisions taken by Benedict XV and to appraise the strategies used to commit the Curia to realization of his own program.