The French enter Rome in order to restore Pope Pius IX to power. This would prove a major obstacle to Italian unification.
The unification of Italy ( [unita dditalja]), also known as the Risorgimento (, Italian: [risordimento]; lit.'Resurgence'), was the 19th-century political and social movement that resulted in the consolidation of different states of the Italian Peninsula into a single state in 1861, the Kingdom of Italy. Inspired by the rebellions in the 1820s and 1830s against the outcome of the Congress of Vienna, the unification process was precipitated by the Revolutions of 1848, and reached completion in 1871 after the Capture of Rome and its designation as the capital of the Kingdom of Italy.Some of the states that had been targeted for unification (terre irredente) did not join the Kingdom of Italy until 1918 after Italy defeated Austria-Hungary in the First World War. For this reason, historians sometimes describe the unification period as continuing past 1871, including activities during the late 19th century and the First World War (19151918), and reaching completion only with the Armistice of Villa Giusti on 4 November 1918. This more expansive definition of the unification period is the one presented at the Central Museum of the Risorgimento at the Vittoriano.
Pope Pius IX (Italian: Pio IX, Pio Nono; born Giovanni Maria Mastai Ferretti; 13 May 1792 – 7 February 1878) was head of the Catholic Church from 1846 to 1878, the longest verified papal reign. He was notable for convoking the First Vatican Council in 1868 and for permanently losing control of the Papal States in 1870 to the Kingdom of Italy. Thereafter he refused to leave Vatican City, declaring himself a "prisoner of the Vatican".
At the time of his election, he was seen as a champion of liberalism and reform, but the Revolutions of 1848 decisively reversed his policies. Upon the assassination of his Prime Minister Rossi, Pius escaped Rome and excommunicated all participants in the short-lived Roman Republic. After its suppression and his return in 1850, his policies and doctrinal pronouncements became increasingly conservative, seeking to stem the revolutionary tide.
In his encyclical Ubi primum he emphasized Mary's role in salvation. In 1854, he promulgated the dogma of the Immaculate Conception, articulating a long-held Catholic belief that Mary, the Mother of God, was conceived without original sin. His 1864 Syllabus of Errors was a strong condemnation against liberalism, modernism, moral relativism, secularization, separation of church and state, and other Enlightenment ideas. Pius definitively reaffirmed Catholic teaching in favor of the establishment of the Catholic faith as the state religion where possible. His appeal for financial support resulted in the successful revival of donations known as Peter's Pence. He centralized power in the church in the Holy See and Roman Curia, while also clearly defining the Pope's doctrinal authority. His chief legacy is the dogma of papal infallibility. Pope John Paul II beatified him in 2000.