Vatican City, officially State of the Vatican City (Latin: Status Civitatis Vaticanae; Italian: Stato della Città del Vaticano), is a landlocked sovereign city-state whose territory consists of a walled enclave within the city of Rome. At approximately 44 hectares (108.7 acres), it is the smallest independent nation in the world and is classified as a microstate.

It was created in 1929 by the Lateran Treaty as a vestige of the much larger Papal States (756 to 1870). Vatican City is a non-hereditary, elected monarchy and is governed by the Bishop of Rome (the Pope). The highest state functionaries are all clergymen of the Catholic Church. It is the sovereign territory of the Holy See (Latin:Sancta Sedes) and the location of the Apostolic Palace—the Pope's official residence—and the Roman Curia. Thus, while the principal ecclesiastical seat (Cathedral) of the Pope as Bishop of Rome (the Basilica of St. John Lateran) is located outside of its walls, in Rome, Vatican City can be said to be the governmental capital of the Catholic Church.

History
Even before the arrival of Christianity, it is supposed that this originally uninhabited part of Rome (the ager vaticanus) had long been considered sacred, or at least not available for habitation. The area was also the site of worship to the Phrygian goddess Cybele and her consort Attis during Roman times. Agrippina the Elder (14 BC – 18 October AD 33) drained the hill and environs and built her gardens there in the early 1st century AD. Emperor Caligula (b. Aug. 31, AD 12 - d. Jan. 24, AD 41, emperor AD 37 to AD 41) started construction of a circus in AD 40 that was later completed by Nero, the Circus Gaii et Neronis. The Vatican obelisk was originally taken by Caligula from Heliopolis to decorate the spina of his circus and is thus its last visible remnant. This area became the site of martyrdom of many Christians after the great fire of Rome in AD 64. Ancient tradition holds that it was in this circus that St. Peter (Simon Peter Bar-Jona) was crucified upside down. Opposite the circus was a cemetery separated by the Via Cornelia. Funeral monuments and mausoleums and small tombs as well as altars to pagan gods of all kinds of polytheistic religions were constructed lasting until before the construction of the Constantinian Basilica of St. Peter's in the first half of the 4th century AD. Remains of this ancient necropolis were brought to light sporadically during renovations by various popes throughout the centuries increasing in frequency during the Renaissance until it was systematically excavated by orders of Pope Pius XII from 1939 to 1941.

In 326, the first church, the Constantinian basilica, was built over the site that Catholic apologists as well as noted Italian archeologists argue was the tomb of Saint Peter, buried in a common cemetery on the spot. From then on the area started to become more populated, but mostly only by dwelling houses connected with the activity of St. Peter's. A palace was constructed near the site of the basilica as early as the 5th century during the pontificate of Pope Symmachus (b. ?? - d. Jul. 19, 514, pope 498 - 514).

Popes in their secular role gradually came to govern 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 created Kingdom of Italy. For much of this time the Vatican was not the habitual residence of the Popes, but rather the Lateran Palace, and in recent centuries, the Quirinal Palace, while the residence from 1309–1377 was at Avignon in France.

In 1870, the Pope's holdings were left in an uncertain situation when Rome itself was annexed by the Piedmontese after a nominal resistance by the papal forces. Between 1861 and 1929 the status of the pope was referred to as the "Roman Question". They were undisturbed in their palace, and given certain recognitions by the Law of Guarantees, including the right to send and receive ambassadors. But they did not recognize the Italian king's right to rule in Rome, and they refused to leave the Vatican compound until the dispute was resolved in 1929. Other states continued to maintain international recognition of the Holy See as a sovereign entity. In practice Italy made no attempt to interfere with the Holy See within the Vatican walls. However, they confiscated church property in many other places, including, perhaps most notably, the Quirinal Palace, formerly the pope's official residence. Pope Pius IX (b. May 13, 1792-d. Feb. 7, 1878, pope 1846-1878), the last ruler of the Papal States, said that after Rome was annexed he was a "Prisoner in the Vatican". This situation was resolved on February 11, 1929 between the Holy See and the Kingdom of Italy. The treaty was signed by Benito Mussolini and Pietro Cardinal Gasparri in behalf of King Victor Emanuel III and Pope Pius XI (b. May 31, 1857-d. Feb. 10, 1939, pope 1922-1939), respectively. The Lateran Treaty and the Concordat established the independent State of the Vatican City and granted 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 position of Catholicism as the Italian state religion