Facing the unresolved problem of roofing the cathedral’s vast octagonal crossing, the Opera del Duomo issued a public call for proposals, drawings, and models—setting the stage for Brunelleschi’s eventual commission.
After the 1418 competition process, Filippo Brunelleschi and Lorenzo Ghiberti were named joint heads for constructing the dome, an arrangement that soon proved contentious but officially launched the project leadership structure.
Work on the cupola began in summer 1420 under the Opera del Duomo, initiating the masonry campaign that would proceed without traditional full wooden centering—an unprecedented logistical and engineering undertaking at this scale.
As construction rose, the dome’s defining structural concept took physical form: two masonry shells tied together by a rib framework (major and minor ribs), reducing weight while maintaining stiffness and stability over the wide span.
To counter outward thrust and help “contain” the masonry, Brunelleschi’s design used circumferential chains (including sandstone blocks reinforced with iron), functioning like tension rings within the dome’s structure.
Masons laid bricks in a herringbone pattern, creating interlocking “self-bracing” sections that helped prevent slippage as the dome curved inward—supporting construction without full centering.
After ongoing disputes and reported technical missteps, Lorenzo Ghiberti was removed from the work’s leadership, leaving Brunelleschi as the effective sole director of the dome’s construction.
With authority consolidated, Brunelleschi carried the project forward through the critical mid-construction years, coordinating the evolving masonry geometry, internal access passages, and worksite organization at height.
By 1433, Ghiberti formally resigned from the dome works, confirming Brunelleschi’s sole primacy over the final push toward completion.
After the dome’s completion, a separate public competition selected the design for the lantern crowning the oculus; Brunelleschi won, but construction was deferred for several years.
Pope Eugenius IV consecrated Santa Maria del Fiore on the Florentine New Year, marking the civic-religious celebration associated with completion of the dome’s main body (though finishing work continued afterward).
Guillaume Dufay’s Nuper rosarum flores was composed for—and first performed at—the 25 March 1436 consecration ceremonies, tying the architectural achievement to a major event in early Renaissance music.
By 1436 the dome structure itself was finished except for the lantern, concluding the main construction campaign that ran from 1420 to 1436 and establishing a landmark of Renaissance engineering and design.
Construction of Brunelleschi's Dome, Florence Cathedral (1420–1436)
