The Papal States, officially the State of the Church, were a series of territories in the Italian Peninsula under the direct sovereign rule of the pope from 756 until 1870. They were among the major states of Italy from the 8th century until the unification of Italy, between 1859 and 1870.
During the Renaissance, the papal territory expanded greatly and the pope became one of Italy's most important secular rulers as well as the head of the Church. At their zenith, the Papal States covered most of the modern Italian regions of Lazio, 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.
However, 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, except the Basilica of St Peter and the papal residence and related buildings around the Vatican quarter of Rome, which the new Italian state did not occupy militarily, despite annexation of Lazio.