1. Santa Maria del Fiore

5. Lantern

6. Construction Timeline • 1331- Wool Guild assumes responsibility for works in Cathedrals • 1357- Guild passes Resolution to build nave and aisle • 1367- Board of experts prepares plan for church and octagonal dome • 1368- Resolution sanctioned for this model • 1417- Opera begins to finance studies, plans, and models for the dome • 1418- Dome design competition announced; no winner declared • 1420- Second competition for single model, according to wishes of Officials of Cupola • 1420-1436- Construction of Dome

7. Construction Statistics • Total weight raised ~29,000 tons; avg. of over 2,000 tons/year and 8 tons/day. • 2 million working hours (270 working days/year) required to complete dome. • Cupola grew an average of 2.5 meters/year. • Several million bricks were laid, on average 400,00 a year. Only a few bricks could be laid per man-hour.

8. Materials Timber– tall white fir from the forests of Casentino Sandstone – from quarry of Trassina-ia. Bricks – from kiln in Via Ghibellina White marble – from quarries of Carrara and Campiglia Metal – mostly iron (for chains, bars, nails, brackets, templates for specific marble parts, etc.) Rope – from Pisa Mortar – prepared from quicklime mixed with sand (or possibly, lime mixed with brickdust)

9. Dome Construction Techniques • Double-masonry dome, with a thick inner octagonal shell connected to a thinner outer shell with meridional arched ribs • 6 horizontal sandstone rings, reinforced by iron chains, resist tensile outward force • Inner dome is so thick that a fairly thick circular ring can be drawn entirely inside it • Pointed dome (pointed fifth) has half the tendency to burst as a shallower, spherical dome • Herringbone brick pattern used to stablize each ring at every level of construction • Supporting drum (14 ft. thick) is octagonal in shape and surrounded on three sides by octagonal half domes

10. St. Peter’s Basilica

13. “By 1506, St. Peter's Basilica, the main church at the Vatican, was too small and decrepit to impress anyone. Following the examples set by emperors and sultans, Pope Julius II decided to crown the old church with a dome. He hired Italian architect Donato Bramante to do the job. Bramante's vision for the Basilica was simple: a Greek cross with equal-sized arms around a central dome, a church with the Pantheon perched on top. But Bramante and the Pope died before much could be built. In 1546, a young artist from Florence named Michelangelo gained total control of the construction of St. Peter's, the largest church in Christendom.”

14. Statistics • Location: Vatican City, Italy • Completion Date: 1626 • Dome Diameter: 138 feet • Dome Type: Ribbed • Height: 452 feet above the street, 390 feet above the floor • Purpose: Religious • Materials: Concrete, brick (masonry) • Architects: Donato Bramante, Michelangelo…

15. Important Dates • 1506- Pope Julius II hires Bramante to create plans for St. Peter’s Basilica and its dome • 1514- Bramante dies, Antonio Sangallo becomes capomaestro • 1546- Sangallo dies, Pope Paul III orders Michelangelo to take the commission • 1564- Michelangelo dies • 1586- della Porta’s plan for a new dome is approved • 1588-1590- Dome constructed jointly by della Porta and Fontana • 1590-1593- Lantern constructed

16. Michelangelo’s Floor Plan (Greek Cross, all arms equal lengths)

18. Tension Rings

19. Internal piers (each ~60 square feet)

20. Internal Spiral Stairwells (inside piers)

21. Buttresses for Dome Support

22. Windows in Drum

23. Lantern “It happened that while the cupola (of San Lorenzo in Florence) was being raised Michelangelo was asked by some of his friends: ‘Shouldn’t you make your lantern very different from that of Filippo Brunelleschi?’ ‘Certainly I can make it different,” he replied, ‘but not better.” -Vasari, Lives of the Artists.

24. Minor Domes One of the two minor domes, designed by Vignola. Vignola served as second in command after Michelangelo’s death and chief architect from 1565 to 1573. (Smaller domes are in style of Bramante’s original cupola; thin walled and single layered)

25. Deviations in Dome Design… • Michelangelo designed a “true,” Roman, hemispherical dome (see book) • Final dome is 20 ft. taller than a hemisphere; the exterior dome is not hemispherical and thus not concentric with the inner shell • Lantern, which is octagonal, suggests that the dome was to have 8 ribs. In actuality, there are 16 ribs.

26. Engravedcoin

27. Additional References • Ackerman, J.S. Michelangelo. Zemmer, London, 1961. • Sketches in Casa Buonarroti.