The origin of the Papal States, which over the years have varied considerably in extent, may be traced back to AD 756 with the Donation of Pepin. However the popes were the de facto rulers of Rome and the surrounding province since the fall of the Roman Empire and the retreat of Byzantine power in Italy. Popes in their secular role ruled portions of the Italian peninsula for more than a thousand years until the mid 19th century, when many of the Papal States were seized by the newly united Kingdom of Italy. In 1870, the pope's holdings were further circumscribed when Rome itself was annexed.
Disputes between a series of "prisoner" popes and Italy were resolved in 1929 by three Lateran Treaties, which established the independent state of Vatican City and granted Roman Catholicism special status in Italy. On 11 February 1929, three treaties were signed with Italy which, among other things, recognized the full sovereignty of the Vatican and established its territorial extent.
In 1984, a concordat between the Holy See and Italy modified certain of the earlier treaty provisions, including the primacy of Roman Catholicism as the Italian state religion.
The pope is elected for life by the College of Cardinals. When the election was last held (Tuesday, April 19, 2005. Benedict XVI), it attracted large crowds. Pope Benedict XVI's predecessor Pope John Paul II's Inauguration Day (he was never crowned) of 22 October 1978 was also a major event.
Present concerns of the Holy See include interreligious dialogue and reconciliation, and the application of church doctrine in an era of rapid change and globalization. About 1 billion people worldwide profess the Catholic faith.