St. Peter's Dome

Michelangelo's dome was only completed to the base when he died. It was later finished by Giacomo della Porta in 1590 The giant letters on a gold background, from St. Veronica to St. Helen, say "Hinc una fides mundo refulgent" (From here a single faith shines throughout the world); and from St. Longinus to St. Andrew: "Hinc sacerdotii unitas exoritur" (From here is born the unity of the priesthood). In the four spandrels which link the square piers and the circular drum, the four Evangelists are portrayed in medallions with a diameter of 8.5 m.: Matthew with the ox, Mark with the lion, Luke with the angel and John with the eagle. Around the base of the drum we can read the solemn words from Matthew's Gospel with which Jesus invests Peter with supreme authority. The text reads: "Tu es Petrus et super hanc petram aedificabo ecclesiam mean et tibi dabo claves regni caelorum" ("You are 'Rock' and on this rock I will build my Church, to you I will give the keys of the kingdom of heaven." Mt 16:18). Above the windows, the dome is divided into sixteen ribs and as many segments, decorated by majestic figures on six ascending concentric levels. Many artists worked on these decorations. Clement VIII commissioned Giuseppe Cesari, known as Cavalier d'Arpino (1568-1640) to carry out the upper part of the decoration. He prepared the cartoons from 1603 to 1612. His drawings were simultaneously transposed into mosaic by the best mosaic artists of the period. From: 'St. Peter's Basilica - A Virtual Tour' by Our Sunday Visitor In fact, the 16th century was coming to an end when Giovanni de' Vecchi and Cesare Nebbia were commissioned to decorate the pediments of the great dome, with the representation in tondos of the four Evangelists: St. John (with the symbol of the eagle), St. Luke (calf), St. Mark (lion) and St. Matthew (angel); the contiguous upper triangles are decorated with angels designed by Cesare Roncalli. This was followed by the decoration of the large dome, divided by 16 vaulting ribs which, within six fields, enclose: at the bottom, the Pope Saints buried in St. Peter's and the large figures of Christ, the Virgin, St. Paul the Baptist and the 12 Apostles; above, inside frames, angels with instruments of passion and heads of cherubs inside round medallions, followed by angels in adoration within frames and finally heads of Seraphims. The iconographic layout, in which the possibility of viewing the details does not affect the overall harmonious vision, was executed by Cavalier d'Arpino who created 65 life-size cartoons painted with tempera, 16 of which were preserved in the Abbey of Montecassino. The transfer to mosaic, executed by the best mosaic artists of the period (Turchi, Torelli, Rossetti, Abatini, Serafini) under the direction of Provenzale, and which continued up to the papacy of Paul V, skillfully expressed the decorative intentions of the artist, with a beautiful chromatic effect. Based on two main colors, the dominant light blue and the vibrant gold, this composition utilizes the diffuse light that penetrates uniformly through the immense intrados, from the large Michelangelo windows, surmounted by curving and alternating triangular architraves and enclosed by coupled pilaster strips. A show of color and lights that enhances the spatial aspect of the architectural structures, instilling deep emotions in the spectator, at any time of the day and from any point of view, that is an effective introduction to a meditative visit to the underlying Confession: the focal point of the origin and construction of St. Peter's two Basilicas - the early-Christian and present-day structures. The decoration of the intrados of the cupola was 1593 onwards in the hands of Giovanni Guerra, Cesare Nebbia, and Marcantonio Bosco, who organized the so-called "exhibitions" to study the effect of their cartoons seen from below. In the four medallions of the corbels below the cupola, (28 feet in diameter), Giovanni De Vecchi portrayed di