Biography

Pope Pius IX (Latin: Pius IX; 13 May 1792 – 7 February 1878), born Giovanni Maria Mastai-Ferretti,[a] reigned from 16 June 1846 to his death in 1878. He was the longest-reigning elected pope in the history of the Catholic Church – over 31 years. During his pontificate, he convened the First Vatican Council (1869–70), which decreed papal infallibility, but the council was cut short due to the loss of the Papal States.