Giovanni Maria Mastai-Ferretti (1792-1878)
Although frought with difficulties, such as the voluntary imprisonment of the popes in the Vatican until 1929, the papacy of Pius IX, called the creator of the modern papacy, was one of extensive growth of the Church. He declared the dogma of the Immaculate Conception of the Blessed Virgin Mary in 1854. He condemned the liberal ideas of the 19th century in his encyclical Quanta Cura (1869), accompanied by the famous Syllabus, which reiterated the condemnation of pantheism, naturalism, socialism, communism, freemasonry, and other doctrinal errors of religious liberalism. He summoned the First Vatican Council and promulgated its decree Pastor Aeternus (1870), in which the nature of the dogma of papal infallibility was defined.