The Cathedral of Florence, begun in the late 13th century and completed almost 150 years later, epitomizes Florentine political and economic dominance in Italy during the Renaissance. Begun in 1296 by the architect Arnolfo di Cambio, the church was constructed on top of the foundations of an early Christian church dedicated to Santa Reparata, and was rededicated to Santa Maria del Fiore. Several architects, including the painter Giotto, continued construction. In the mid-1300s, Francesco Talenti took over and is credited with designing the dome, which, with its 138-foot diameter, was to be the largest dome constructed in Italy since antiquity. The church is a traditional basilica-plan construction, with side aisles flanking a wider central nave that leads the visitor to a massive crossing lined with side chapels and a high altar. The nave was finally completed in 1380, at which time the church lacked only its dome.
The dome project was problematic, however, as no architect was able to come up with a plan that would allow the builders to span the width of the drum with scaffolding, nor did the completed lower level allow for the use of external buttressing, aside from the exedrae, or side chapels, to help support the lower walls of the choir area. A competition was therefore held in 1418 requesting proposals for the dome, and several of these plans still exist in the Florentine archives today. Since the dome site was too high for scaffolding, stories tell of one ingenious plan that consisted of placing a massive pile of dirt in the nave crossing that would be tall enough to provide a platform for the construction of the dome. Upon completion of the dome, the dirt could be carried away by children, encouraged to help find gold florins buried in the soil.
The solution selected by the Arte della Lana, however, was that of Filippo Brunelleschi, an architect who had just returned from Rome, where he focused his studies on Ancient Roman architecture, including the Pantheon.Brunelleschi had already advised the consanction of a tall drum, completed in 1410. On top of that, Brunelleschi's solution involved the construction of a double-shelled dome that had no lateral thrust, but instead directed its weight into the drum via a series of horizontal tension chains made of wood and iron set at the base of the dome. Without scaffolding, Brunelleschi designed hoisting machines that would bring materials up to the consanction site, a great feat of engineering. Although concrete was used to build the dome of the Pantheon, its material components were unknown in the Renaissance, and therefore Brunelleschi used brick for the construction of his dome. Given the octagonal shape of the drum, Brunelleschi's solution was a mixture of the Gothic ribbed and pointed arch combined with a classical brickwork, oculus, and lantern. The brick played a pivotal role in the construction of the interior dome by creating, through the use of a herringbone pattern, brick layers that were interconnected. Vertical marble ribs and horizontal sandstone rings reinforced the overall shape of the dome, which was held together by oak beams tied together to form the outer ribs. Arches connected the two shells together, creating an internal walkway that allowed access into the lantern.
The church was consecrated in 1436, although the lantern was not fully completed until 1471, years after Brunelleschi's death. The arcade gallery that Brunelleschi designed to be located right above the drum was partly constructed in the early 1500s by Baccio d'Agnolo, but remains incomplete today. Brunelleschi's innovative solution to an overly ambitious project subsequently ushered in the Renaissance, with its classically inspired structures built on the scale of Ancient Roman monuments. Thus, "the Duomo," as the Cathedral of Florence came to be called, asserted with its wide diameter and great height the superiority of Florence during the early Renaissance, and on a scale that was not superseded until the next century, with the construction of Saint Peter's Church in Rome.