Vatican City — formally known as the State of the Vatican City or Vatican City State (Latin: Status Civitatis Vaticanæ and Italian: Stato della Città del Vaticano) — is a sovereign landlocked enclave surrounded by Rome, Italy. The modern-day home of the popes, it is the smallest independent state in the world in terms of area and population. Its borders are coextensive with the Holy See, the ecclesiastical seat of the Roman Catholic Church and its Eastern Rite.
The Head of State is the Pope; the Heads of Government are the Secretary of State and Governor of Vatican City (sometimes referred to as the President of Vatican City). Currently, they are Pope Benedict XVI of Germany, Angelo Cardinal Sodano of Italy and Edmund Cardinal Szoka of the United States, respectively. The governance of the Holy See is separate, consisting of the Roman Curia in turn consisting of members of the College of Cardinals. The Heads of Government are concurrently agents of the Roman Curia.
The city takes its name from Mons Vaticanus, also known as Vatican Hill. Mons Vaticanus and the adjacent Vatican Fields upon which St. Peter's Basilica and its Sistine Chapel, Apostolic Palace and museums were built, predates Christendom.
It is supposed that this originally uninhabited part of Rome (the ager vaticanus) had always been considered sacred, even before the arrival of Christianity. In 326 the first church, Constantine's basilica, was built over the supposed site of the tomb of Saint Peter, and from then on the area started to become more populated.
Popes in their secular role gradually extended their control over neighbouring regions and, through the Papal States, ruled a large portion of the Italian peninsula for more than a thousand years until the mid 19th century, when most of the territory of the Papal States was 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 on February 11, 1929 by three Lateran treaties, which established, under Mussolini, the independent state of the Vatican City and granted Roman Catholicism special status in Italy. In 1984, a new concordat between the Holy See and Italy modified certain provisions of the earlier treaty, including the primacy of Roman Catholicism as the Italian state religion.