Le terme Vatican désignait jadis la zone marécageuse située sur la rive droite du Tibre, entre le Ponte Milvio et l'actuel Ponte Sisto.

Dans l'antiquité, pendant la période royale et tout au long de l'époque républicaine, le territoire était connu sous le nom d'Ager Vaticanus et s'étendait au nord jusqu'à l'embouchure du Crémère, et au sud au moins jusqu'au Janicule. A l'époque impériale, à partir du IIe siècle après J.-C., le toponyme Vaticanum est attesté, comprenant une zone correspondant à peu près à l'actuel État de la Cité du Vatican. A l'époque romaine, la zone, située en dehors de la ville de Rome, est bonifiée et occupée par des villas, par les jardins d'Agrippine –  mère de l'empereur Caligula (37-41 ap. J.-C.) –  et par de vastes nécropoles disposées le long des principales artères. Dans les jardins de sa mère, Caligula construisit un petit cirque pour l'entraînement des chars (Gaianum), rénové par la suite par Néron (54-68 ap. J.-C.), où, selon la tradition, Pierre souffrit le martyre lors de la grande persécution contre les chrétiens ordonnée par Néron en 64 ap. J.-C.

Le long de la Via Trionfale, qui part de la place Saint-Pierre vers le nord en direction de Monte Mario, plusieurs ensembles de tombes ont été fouillés, tandis que le long de la Via Cornelia, qui allait vers l'ouest, s'élevait la Nécropole dans laquelle se trouve également la tombe de l'apôtre Pierre. La présence de Pierre établit le point topographique le plus important de la zone qui, depuis lors et pendant deux millénaires, est devenu la destination du plus important des pèlerinages chrétiens : de nombreux croyants, animés par le désir de rester proches de saint Pierre, cherchaient à recevoir une sépulture  à côté de lui. La Nécropole a été enterrée lors de la construction de la Basilique dédiée à l'apôtre, décidée par l'empereur Constantin (306-337 ap. J.-C.), qui a déterminé tout le développement ultérieur de la zone. Après avoir libéralisé le culte de la religion chrétienne par le célèbre édit de Milan en 313, l'empereur Constantin commença vers 324 la construction d'une grande église à cinq nefs, transept et abside terminale, au centre de laquelle se trouvait le tombeau de Pierre. Une volée de marches et un quadriportique, dans lequel les non-baptisés devaient s'arrêter, complétaient l'ensemble.  Pendant ce temps, le cirque de Néron tombait progressivement en ruine, notamment parce que nombre de ses pierres étaient utilisées pour la construction de la nouvelle église qui, en peu de temps, devint un nouveau pôle d'attraction pour la ville. Et c'est précisément pour conserver et protéger la mémoire de Pierre que, quelques années plus tard, Léon IV (847-855) construira les premiers murs de la civitas qui en son honneur fut nommée  « Leoniana » (Cité léonine) et qui constituera le noyau spirituel de la nouvelle Rome médiévale et de la Renaissance. Bien que les Papes résidaient alors dans le Palais du Latran, un certain nombre d'édifices ont été construits dans la zone entourant Saint-Pierre au cours du Moyen Age. C'est notamment sous Eugène III (1145-1153) et Innocent III (1198-1216) que fut construit le premier palais, agrandi par la suite entre la fin des années 1200 et le début des années 1300, et que les murs léonins furent rénovés. Mais à partir de 1309, le siège papal est transféré à Avignon ; Rome et la basilique Saint-Pierre restent alors abandonnées pendant plus d'un siècle. Il faudra attendre une cinquantaine d'années jusqu'en 1377, année du retour de la papauté à Rome, pour que la ville retrouve son lustre. Au milieu du XVe siècle, le problème d'une éventuelle reconstruction complète de la basilique Saint-Pierre est abordé pour la première fois.

Le Pape Nicolas V (1447-1455) fait établir par l'architecte Bernardo Rossellino un projet d'agrandissement de la Basilique, avec une nouvelle abside faisant saillie par rapport l'abside constantinienne : celui-ci ne sera que commencé car, quelques années plus tard, l'avancée des Turcs et la chute de Constantinople obligent à abandonner les travaux. Entre 1477 et 1480, le Pape Sixte IV (1471-1484) entreprend la construction d'une grande chapelle, qui fut appelée Sixtine pour rappeler son nom : décorée de fresques réalisées par les plus grands peintres italiens de l'époque, elle est inaugurée le 15 août 1483. De grands changements furent réalisées par le Pape Jules II (1503-1513), qui transforma radicalement la citadelle. Il entreprit de démolir la basilique constantinienne, commença les travaux de la nouvelle Basilique Saint-Pierre et construisit la célèbre Cour du  Belvédère pour relier le petit palais du Belvédère de son prédécesseur Innocent VIII (1484-1492), au nord, au noyau des bâtiments médiévaux, au sud ; il appela également Raphaël et Michel-Ange à Rome pour peindre à fresque les appartements du Pape.  D'autres travaux ont été réalisés au cours du même siècle : la basilique Saint-Pierre, qui après diverses vicissitudes a été conçue et commencée dans son noyau central par Michel-Ange au milieu du XVIe siècle, a été recouverte d'une grandiose coupole « voûtée » par Giacomo Della Porta. L'église fut ensuite agrandie par Carlo Maderno au début du XVIIe siècle, avec l'ajout de deux travées dans le bras longitudinal, et complétée par le Bernin, au milieu du XVIIe siècle, avec la grandiose place bordée de deux hémicycles de quadruples rangées de colonnes qui lui ont donné son aspect baroque actuel, reliant ce lieu de prière au reste de la ville.

In ancient times, the word Vatican referred to the swampy area on the right bank of the Tiber River, including the area between Ponte Milvio and today’s Ponte Sisto.

During the royal period and throughout the Republican Age, the territory was known as Ager Vaticanus and stretched as far north as the Mouth of the Cremera, and as far south as the Janiculum Hill. The earliest records of the use of the word Vaticanum to refer to the area that roughly corresponds to today’s Vatican City State, date back to the 2nd century A.D., in the Imperial Age. In the Roman era, the area outside the city of Rome was reclaimed and villas began to appear, among them the gardens of Agrippina, mother of Caligula (37-41 A.D.), as well as a vast necropolis  along its main arterial roads. Caligula had a small circus built in his mother’s gardens, as a training site for charioteers (Gaianum). Later renovated by Nero (54-68 A.D.), tradition says it was the place where Saint Peter was martyred during the great persecution of Christians in 64 A.D.

Several clusters of tombs were found along Via Trionfale that leads north from the Basilica of Saint Peter towards Monte Mario, and a necropolis was discovered along Via Cornelia leading west, in which the tomb of the Apostle Peter was found. The presence of Peter established the topographic fulcrum of the area, and since then and for two whole millennia, it remains one of the most important Christian pilgrimage sites. Indeed, spurred by the desire to be close to Saint Peter, many ended up being buried close to him. The Necropolis was buried during the construction of the Basilica dedicated to the Apostle, built by Emperor Constantine (306-337 A.D.) which defined later developments in the area. After the Edict of Milan in 313 A.D. with which he granted Christians the freedom to practice their religion, some time around 324 A.D., Emperor Constantine started the construction of a large church with five naves, a transept and a terminal apse, at the centre of which, lay the tomb of Saint Peter. It included a stairwell and a quadriporticus, which the non-baptized could not enter.

In the meantime, Nero’s circus fell into ruins, many of its stones having been removed for use in the construction of the new church, which did not take long to become a new source of attraction to the city Years later, Leo IV (847-855) chose the same site, in memory of Peter, to build the first walls of the civitas, which became known as Leonine, the spiritual heart of Rome throughout the Middle Ages and the Renaissance. Despite the fact that the popes still lived in the Lateran Palace, buildings began to be appear in the area adjacent to Saint Peter’s Basilica in the Middle Ages. The first palace was completed in the Middle ages, during the Pontificates of Eugene III (1145-1153) and Innocent III (1198-1216), and expanded between the end of the 1200s and the early 1300s, when the Leonine Walls underwent restoration works. However, in 1309, the Papal See was moved to Avignon and both Rome and the Basilica of Saint Peter were abandoned for over a century. It took 50 years from the Pope’s return in 1377, to polish up the city. By the mid-1400s, the idea of an integral reconstruction of Saint Peter’s Basilica began to surface.

Pope Nicholas V (1447-1455) commissioned architect, Bernardo Rossellini, to draft a project for the expansion of the Basilica, with a new apse, that was more protruding than the one Constantine had built. Its construction was left in its initial stages, as Turkish groups advanced ever closer, culminating in the fall of Constantinople and the abandonment of the project. Between 1477 and 1480, Pope Sixtus IV (1471-1484) ordered the construction of a large chapel, which was later named after him, the Sistine Chapel. Decorated with frescoes by the greatest Italian painters of the time, it was inaugurated on 15 August 1483. Julius II (1503-1513) made many changes that radically changed the citadel. He began the demolition of Constantine’s Basilica and started the construction of a new Saint Peter’s Basilica. He built the famous Belvedere courtyard that connects the Villa Belvedere of his predecessor Innocent VIII (1484-1492) in the north, to the medieval buildings in the south, and he commissioned Raphael and Michelangelo to paint frescoes in the papal apartments and in the Sistine Chapel, respectively.

Additional work took place during that century. After a series of events, the Basilica of Saint Peter was designed and Michelangelo began work in its fulcrum in the mid-1500s. The Church was covered by a grand vaulted cupola by Giacomo Della Porta. It was later further expanded by Maderno in the early 1600s with the addition of two aisles in the longitudinal section, and completed by Bernini in the second half of the 17th century, with the grand square and the two semicircles of four rows of columns which give it its baroque look, and connects the Basilica to the rest of the city.

VATICAN CITY IN 1932

With a surface area of 0.44 hectares, Vatican City State is the smallest independent State in the world, both in terms of population and territory. Its borders are marked by its walls, and in Saint Peter’s Square, by the white marble line that joins the two wings of the colonnade. In addition to its proper territory, in a certain sense the Vatican stretches to Rome and beyond Rome, to places that have the right to “extraterritoriality”.

Vatican City State arose from the Lateran treaty signed on 11 February 1929 between the Holy See and Italy, which recognized it as a sovereign state subject to International Law, created to assure to the Holy See, in its role as supreme institution of the Catholic Church, an “absolute and visible independence” and “to guarantee it indisputable sovereignty also in the international arena”, as stated in the preamble of the Treaty.

The Catholic Church carries out her evangelic mission through the particular churches and the local churches via its central government, constituted by the Supreme Pontiff and by the Bodies that assist him in exercising his responsibilities to the universal Church (Holy See).

Its form of government is an absolute monarchy. The Supreme Pontiff is the Head of State with full legislative, executive and judicial power. In sede vacante, these powers are passed on to the College of Cardinals. The legislative power is also carried out in his name, by a Commission of Cardinals and other members and headed by the Cardinal President, appointed for a five-year term. The executive power is transferred to the President of the Commission, who in this role, takes on the name of President of the Governorate and is assisted by the General Secretary and by the Vice General Secretary. The President is responsible for the Directorates and Central Offices of theGovernorate, the collection of bodies and entities through which this power is exercised. Judicial power is exercised on the Supreme Pontiff’s behalf by the bodies of the judicial system

Vatican City State has its own flag, divided vertically into two: the yellow part is on the side of the flagpole while the other side is white and depicts the pontifical tiara and the crossed keys. It mints its own coins, which currently is the Euro, and issues its own postage stamps. It has a daily newspaper, L’Osservatore Romano, which was founded in 1861, and since 1931, its own radio station, Vatican Radio which transmits throughout the world in various languages.

The security of the Pope and of the State is guaranteed by the Pontifical Swiss Guard, founded in 1506, whose uniforms, according to tradition, were designed by Michelangelo, and by the Pontifical Gendarmerie Corps, which provides police services and security to the State.