Michelangelo's Vision
The dome of St. Peter's Basilica was conceived and designed by Michelangelo Buonarroti, who worked on it until his death in 1564 at age 88. Though he never saw it completed, his architectural vision defined one of the most recognizable silhouettes in the world.
After Michelangelo's death, architects Giacomo della Porta and Domenico Fontana brought the dome to completion between 1588 and 1590—an astonishing feat accomplished in just 22 months thanks to the tireless work of 800 laborers working around the clock.
Engineering Marvel
The dome features a "double-shell with cavity" construction, giving it the elegant ogival shape slightly slenderer than Michelangelo's original hemispherical design. This engineering innovation reduced weight while maintaining structural integrity.
On November 18, 1593, the large gilded bronze sphere surmounted by the cross—the work of Sebastiano Torrigiani—was placed atop the lantern, completing the dome's majestic silhouette.
"TV ES PETRVS ET SVPER HANC PETRAM AEDIFICABO ECCLESIAM MEAM ET TIBI DABO CLAVES REGNI CAELORVM"
"You are Peter and on this rock I will build my church and give you the keys to the Kingdom of Heaven" (Matthew 16:18-19) — inscribed in blue letters on gold around the dome's base.
The Mosaic Decorations
Pope Clement VIII commissioned the dome's magnificent mosaic decoration between 1598 and 1613, under the direction of Marcello Provenzale. The approximately 3,000 square meters of mosaic surface is divided into sixteen wedge-shaped compartments.
From top to bottom, the hierarchy of figures includes: the Eternal Father with outstretched hand in blessing, Seraphim, Angels, Cherubim, more Angels (some carrying symbols of the Passion), Christ with the Virgin Mary, Saint John the Baptist, Saint Paul and the Apostles, and finally Patriarchs and Bishops.