The Obelisco Vaticano (25.5 m), which graces the centre of Piazza di San Pietro, once stood in the city of Alexandria, if Pliny the Elder (c. 23-79) is to be believed. The obelisk was moved to Rome in 40 CE, on the order of the emperor Caligula (r. 37-41), who had it erected on the spina of the Vatican Circus, later the site of St Peters Basilica. The Vatican obelisk is the only ancient obelisk to have remained standing; all of the others collapsed or were toppled. St Peter's Needle, as the obelisk came to be called, originally stood on the south side of the Basilica, but in 1586 it was moved to its present position, at the behest of Pope Sixtus V (r. 1585-90). The man who was charged with moving the obelisk (which weighs in the region of 300 tons) and re-erecting it (a task not undertaken for more than a thousand years) was the architect Domenico Fontana (1543-1607).
The raising of the obelisk, which took place on September 10th 1586, involved a team of 900 men and dozens of horses.
At its base sit four bronze lions, each of which has two bodies with intertwining tails. The lions, and the stars on their heads, are a reference to the heraldic alms of Sixtus V. There are further references at the top of the obelisk in the form of the montini and star. They replaced the gilded bronze globe, which is now in the Musei dei Conservatori. According to legend, the globe was supposed to contain the ashes of either Julius Caesar or St Peter. However, it turned out to be quite empty. At the very top of the obelisk is a cross.
The Vatican obelisk sports several inscriptions. Two ancient inscriptions at the base of the shaft proclaim: DIVO CAESARI DIVI F AVGVSTO TI CAESARI DIVI AVGVSTI F AVGVSTO SACRVM. (Sacred to the Divine Caesar Augustus, son of the Divine, to Tiberius Caesar Augustus, son of the Divine Augustus.)
The four inscriptions on the pedestal were composed by Cardinal Silvio Antoniano.
South face: SIXTVS V PONT MAX / OBELISCVM VATICANVM / DIS GENTIVM / IMPIO CVLTV DICATVM / AD APOSTOLORVM LIMINA / OPEROSO LABORE TRANSTVLIT / ANNO M D LXXXVI PONT II. (Sixtus V, Pontifex Maximus, by a laborious task, transferred to the threshold of the Apostles the Vatican obelisk, dedicated in impious reverence to the gods of the heathen, in the year 1586, the second of his pontificate.)
North face: SIXTVS V PONT MAX / CRUCI INVICTAE / OBELISCVM VATICANVM / AB IMPVRA SVPERSTITIONE / EXPIATVM IVSTIVS / ET FELICIVS CONSECRAVIT / ANNO MDLXXXVI PONT II. (Sixtus V, Pontifex Maximus, consecrated to the invincible cross the Vatican obelisk, expiated of impure superstition, in the year 1586, the second of his pontificate.) At a much lower level, and in smaller script, is an acknowledgement of Domenico Fontana's role: DOMINICVS FONTANA EX PAGO MILI / AGRI NOVOCOMENSIS TRANSTVLIT / ET EREXIT. (Domenico Fontana, of the town of Mili in the territory of Como, moved and erected this.)
East face: ECCE CRVX DOMINI / FVGITE / PARTES ADVERSAE / VICIT LEO / DE TRIBV IVDA. (Behold, the Cross of the Lord. Take flight hostile ranks, the Lion of the Tribe of Judah, has conquered.)
West face: CHRISTVS VINCIT / CHRISTVS REGNAT / CHRISTVS IMPERAT / CHRISTVS AB OMNI MALO / PLEBEM SVAM / DEFENDAT. (Christ conquers. Christ reigns. Christ commands. May Christ defend his people from all evil.)