the city is or, more formally, , meaning 'Vatican City State'. Its Latin name is ; this is used in official documents by the Holy See, the Church and the Pope. History Early history The name "Vatican" was already in use in the time of the Roman Republic for the Ager Vaticanus, a marshy area on the west bank of the Tiber across from the city of Rome, located between the Janiculum, the Vatican Hill and Monte Mario, down to the Aventine Hill and up to the confluence of the Cremera creek. Because of its vicinity to Rome's archenemy, the Etruscan city of Veii (another naming for the Ager Vaticanus was Ripa Veientana or Ripa Etrusca), and for being subjected to the floods of the Tiber, the Romans considered this originally uninhabited part of Rome dismal and ominous. The particularly low quality of Vatican wine, even after the reclamation of the area, was commented on by the poet Martial (40 – between AD 102 and 104). Tacitus wrote that in AD 69, the Year of the Four Emperors, when the northern army that brought Vitellius to power arrived in Rome, "a large proportion camped in the unhealthy districts of the Vatican, which resulted in many deaths among the common soldiery; and the Tiber being close by, the inability of the Gauls and Germans to bear the heat and the consequent greed with which they drank from the stream weakened their bodies, which were already an easy prey to disease". The toponym Ager Vaticanus is attested until the 1st century AD: afterwards, another toponym appeared, Vaticanus, denoting an area much more restricted: the Vatican Hill, today's St. Peter's Square, and possibly today's Via della Conciliazione. Under the Roman Empire, many villas were constructed there, after Agrippina the Elder (14 BC–18 October AD 33) drained the area and laid out her gardens in the early 1st century AD. In AD 40, her son, Emperor Caligula (31 August AD 12–24 January AD 41; r. 37–41) built in her gardens a circus for charioteers (AD 40) that was later completed by Nero, the , usually called, simply, the Circus of Nero. The Vatican Obelisk was originally taken by Caligula from Heliopolis in Egypt 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