Pius XI = Pio XI

b. 31 May 1857, Desio, Province of Milan, Italy
d. 10 Feb 1939, Vatican City

Title: Sommo Pontefice, Sovrano dello Stato della Città del Vaticano (Supreme Pontiff, Sovereign of the State of the Vatican City)
Term: 7 Jun 1929 - 10 Feb 1939
Chronology: 6 Feb 1922, elected, meeting of the College of Cardinals (conclave), Cappella Sistina, Palazzi Apostolici, Vatican City [1]
  12 Feb 1922, crowned, Basilica di San Pietro in Vaticano, Vatican City [1]
  7 Jun 1929, Vatican City becomes a sovereign state upon the exchange of ratified copies of the Treaty of Lateran, private ceremony, Sala delle Congregazioni, Palazzi Apostolici, Vatican City (signed 11 Feb 1929, effective upon the exchange of ratifications in accordance with Art. 4 of the Law No. 810 of 27 May 1929) [2]
  10 Feb 1939, died
Names/titles: Baptized (1 Jun 1857): Ambrogio Damiano Achille Ratti
  See a note on other titles
Biography:
Born in the family of a silk factory owner; attended seminaries at Seveso, Monza and Milan; ordained priest in Rome (20 Dec 1879) and embarked on academic career within the Church; studied in Rome (1879-1882); earned three doctorates in theology, canon law and philosophy; returned to Milan to become professor of theology and rhetorics; served as a staff member (1888-1907) and prefect (1907-1911) of the Ambrosian Library ; was made domestic prelate of His Holiness (1907); appointed pro-prefect of the Vatican Library (1912-1914) and then promoted to prefect (1914-1918); continued his service as diplomat and was assigned to represent the pope as apostolic visitor to Poland and Lithuania (1918-1921) and was also appointed nuncio in Poland (1919-1921); elected titular archbishop of Lepanto (3 Jul 1919); was transferred to the titular see of Adana (29 Apr 1921); created cardinal priest in the consistory of 13 Jun 1921; received the red hat and the title of Ss. Silvestro e Martino ai Monti (16 Jun 1921); was transferred to metropolitan see of Milan (13 Jun 1921); participated in the conclave of 1922 and was elected pope (6 Feb 1922), taking the name of Pius XI; supervised the signing of the Lateran Treaties with the Italian government (1929), recognizing the full sovereignty of the Holy See in the State of Vatican City.
Biographical sources: "Between two wars. The Story of Pope Pius XI (Achille Ratti) 1922-1939", by Robin Anderson (Chicago: Franciscan Herald, 1977).

[1] "Annuario Pontifico. 1939." (Città del Vaticano: Tipografia Poliglotta Vaticana, 1939).
[2] Gazzetta Ufficiale del Regno d'Italia, Mercoledi, 5 giugno 1929, Numero 130 (Straordinario), pp. 2501-2505; Gazzetta Ufficiale del Regno d'Italia, Sabato, 8 giugno 1929, Numero 133, p. 2570.
  Image: photograph, c. 1930.