>> Early history of Vatican City

The name "Vatican" was already in use in the time of the Roman Republic for a marshy area on the west bank of the Tiber across from the city of Rome. 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 Circus Gaii et Neronis, usually called, simply, the Circus of Nero.

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.[citation needed] A shrine dedicated to the Phrygian goddess Cybele and her consort Attis remained active long after the Constantinian Basilica of St. Peter was built nearby.

View of St. Peter's Square from the top of Michelangelo's dome

The particularly low quality of Vatican wine, even after the reclamation of the area, was commented on by the poet Martial (40 – between 102 and 104 AD). 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 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 AD 64. Ancient tradition holds that it was in this circus that Saint Peter 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. 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. The Constantinian basilica was built in 326 over what was believed to be the tomb of Saint Peter, buried in that cemetery.

From then on, the area became more populated in connection with activity at the basilica. A palace was constructed nearby as early as the 5th century during the pontificate of Pope Symmachus (reigned 498–514).
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