Information about Papal States.
The Papal States, officially the State of the Church (Italian: Stato della Chiesa; Latin: Status Ecclesiae) were territories in the Italian Peninsula under the sovereign direct rule of the pope, from the 8th century until 1870. They were among the major states of Italy from roughly the 8th century until the Italian Peninsula was unified in 1861 by the Kingdom of Piedmont-Sardinia. At their zenith, they covered most of the modern Italian regions of Lazio (which includes Rome), Marche, Umbria and Romagna, and portions of Emilia. These holdings were considered to be a manifestation of the temporal power of the pope, as opposed to his ecclesiastical primacy.
By 1861, much of the Papal States' territory had been conquered by the Kingdom of Italy. Only Lazio, including Rome, remained under the Pope's temporal control. In 1870, the pope lost Lazio and Rome and had no physical territory at all, not even the Vatican. Italian Fascist leader Benito Mussolini ended the crisis between unified Italy and the Vatican by signing the Lateran Treaty granting the Vatican City State sovereignty.