"Pope Saint John XXIII (Latin: Ioannes XXIII), born Angelo Giuseppe Roncalli reigned from 28 October 1958 to his death in 1963.
He was ordained a priest on 10 August 1904 and served in a number of posts, including papal nuncio in France and a delegate to Bulgaria, Greece and Turkey. In a consistory on 12 January 1953 Pope Pius XII made Roncalli a cardinal as the Cardinal-Priest of Santa Prisca in addition to naming him the Patriarch of Venice.
Roncalli was elected pope on 28 October 1958 at age 77 after 11 ballots. His selection was unexpected, and Roncalli himself had come to Rome with a return train ticket to Venice. He was the first pope to take the pontifical name of "John" upon election in more than 500 years, and his choice settled the complicated question of official numbering attached to this papal name due to the antipope of this name.
Pope John XXIII surprised those who expected him to be a caretaker pope by calling the historic Second Vatican Council (1962–65), the first session opening on 11 October 1962. He did not live to see it to completion. John died of stomach cancer on 3 June 1963, four and a half years after his election and two months after the completion of his final and famed encyclical, Pacem in Terris."
He was beatified on 3 September 2000 by Pope John Paul and declared a saint by Pope Francis on 5 July 2013, based on his merits of opening the Second Vatican Council. He was canonised on 27 April 2014. His feast day is 11 October, the day of the first session of the Second Vatican Council.