In 1864 Pope Pius IX, a man who had fallen out of favor and had fled Italy due to his meddling in national affairs, returned from exile and wrote Syllabus of Errors, a work devoted to condemning certain liberalizing social trends and claiming that the Church should have control over all secular affairs in the Papal States. At the Vatican Council in 1870 he established the dogma of Papal infallibility.
Impact: Along with his 1854 dogma of the Immaculate Conception, his rule on Papal infallibility remains as a dogma of the Catholic Church. Pius, however, retired as a prisoner to the Vatican after he refused to accept the abolishment of Vatican rule over the Papal States, which were made part of Italy. He died in prison.