When the cardinals elected Angelo Roncalli Pope on October 20, 1958, many regarded the 76-year-old as a transitional pope, little realising that his pontificate would mark a turning point in history and initiate a new age for the Church.
Angelo Giuseppe Roncalli, the third of 13 children, was born on November 25, 1881 at Sotto il Monte (Bergamo) to a family of sharecroppers. He attended elementary school in the town, was tutored by a priest of Carvico, and at the age of 12 entered the seminary at Bergamo.
A scholarship from the Cerasoli Foundation (1901) enabled him to go on to the Apollinaris in Rome where he studied under (among others) Umberto Benigni, the Church historian.
He interrupted his studies for service in the Italian Army but returned to the seminary, completed his work for a doctorate in theology, and was ordained in 1904.
Continuing his studies in canon law he was appointed secretary to the new Bishop of Bergamo, Giacomo Radini-Tedeschi. Angelo served this social-minded prelate for nine years, acquiring first-hand experience and a broad understanding of the problems of the working class. He also taught apologetics, Church history, and patrology.
With the entry of Italy into World War I in 1915, he was recalled to military service as a chaplain.
On leaving the service in 1918, he was appointed spiritual director of the seminary, but found time to open a hostel for students in Bergamo. It was at this time also that he began the research for a multi-volume work on the episcopal visitation of Bergamo by St Charles Borromeo, the last volume of which was published after his elevation as Pope.
In 1921 he was called to Rome to reorganize the Society for the Propagation of the Faith. Nominated titular archbishop of Areopolis and apostolic visitator to Bulgaria (1925), he immediately concerned himself with the problems of the Eastern Churches.
Transferred in 1934 to Turkey and Greece as Apostolic Delegate, he set up an office in Istanbul for locating prisoners of war.
In 1944 he was appointed Nuncio to Paris to assist in the Church's post-war efforts in France, and became the first permanent observer of the Holy See at UNESCO, addressing its sixth and seventh general assemblies in 1951 and 1952. In 1953 he became Cardinal-Patriarch of Venice, and expected to spend his last years there in pastoral work.
He was correcting proofs of the synodal Acts of his first diocesan Synod (1958) when he was called to Rome to participate in the conclave that elected him Pope.
READ FULL BIOGRAPHY: Pope John XXIII - 1958-1963 (Vatican)
John XXIII (Berkley Centre, Georgetown University)
John XXIII (Encyclopedia Brittanica)