Events in the year 1931 in Vatican City.
- 12 February – Vatican Radio is formally established and inaugurated by Pope Pius XI and Guglielmo Marconi.
- 26 April – Pope Pius XI writes a chirograph titled Dobbiamo Intrattenerlato ("We must Entertain Her") to the Archbishop of Milan Alfredo Ildefonso Schuster, defending the purpose of the now-disassembled Italian Catholic Action, and correcting any misconceptions.
- 15 May – Pope Pius XI publishes the minor encyclical Quadragesimo anno ("Fortieth year"), which restates the points of the encyclical Rerum novarum of Pope Leo XIII in illustrating the complex relationship between companies and workers that characterize "social Catholicism".
- 29 June – Pope Pius XI publishes the first of three major encyclicals titled the Non Abbiamo Bisogno ("We Do Not Need to Acquaint You"), which challenges totalitarian government's policies against Christian values, referencing mainly Fascist Italy in his text.
- 2 September – The letters of protest directed towards the Fascist Italian government in the Dobbiamo Intrattenerla and Non Abbiamo Bisogno obtain partial success, with an agreement being signed with the Italian government recognizing again the Italian Catholic Action, but in a weaker diocesan form without a central direction.
- 2 October – Pope Pius XI publishes the minor encyclical Nova impendet ("New Questions Threaten"), in which he addresses the economic crisis affecting many unemployed workers partnered with the rise in military spending among nations.
- 25 December – Pope Pius XI publishes the minor encyclical Lux Veritatis ("Light of Truth"), which discusses the heresy of Nestorius and reaffirms the divine motherhood of Mary towards the Council of Ephesus.
There were no deaths in the year 1931 in Vatican City.
- ^ Scarisbrick, Veronica. "12 February 1931: Inauguration of Vatican Radio". vaticannews.va. Retrieved 1 June 2022.
- ^ "il primo radiomessaggio di Papa Pius XI a tutte le genti e ad ogni creatura (Pope Pius XI's first radio message to all people and every creature)". vatican.va (in Italian). Retrieved 1 June 2022.
- ^ XI, Pope Pius. "Chirografo di Sua santità Pio XI "Dobbiamo Intrattenerla" all'em.mo Cardinale Presbitero Alfredo Ildefonso Schuster Arcivescovo di Milano in difesa dell'azione Cattolica Italiana (Chirograph of His holiness Pius XI "Dobbiamo Intrattenerla" to the most Cardinal Priest Alfredo Ildefonso Schuster Archbishop of Milan in defense of the Italian Catholic Action)". vatican.va. Retrieved 2 June 2022.
- ^ XI, Pope Pius. "Quadragesimo Anno". vatican.va. Retrieved 1 June 2022.
- ^ a b c "Pio XI (1857-1939) (Pius XI (1857-1939))". vatican.va (in Italian). Retrieved 1 June 2022.
- ^ XI, Pope Pius. "Non Abbiamo Bisogno". vatican.va. Retrieved 1 June 2022.
- ^ Petruzzello, Melissa. "Pius XI". britannica.com. Encyclopædia Britannica. Retrieved 1 June 2022.
- ^ XI, Pope Pius. "Nova Impendet". vatican.va. Retrieved 2 June 2022.
- ^ XI, Pope Pius. "Lettera enciclica Lux Veritatis (Encyclical letter Lux Veritatis)". vatican.va (in Italian). Retrieved 2 June 2022.
- ^ "Lux Veritatis". catholic.net. Retrieved 2 June 2022.
- ^ Ludwig Volk Das Reichskonkordat vom 20. Juli 1933.
- ^ Kunst, Father Richard. "February 7, 1930: Pope Pius XI Appoints Cardinal Eugenio Pacelli, Secretary of State, & Commentary by Father Richard Kunst". papalartifacts.com. Retrieved 24 May 2022.
- ^ Milestones TIME Magazine 11 August 1961.