The genius of the Florentine architects

Brunelleschi was born in Florence in 1377 and began his career as a goldsmith and sculptor: in 1401, he took part in the competition for the second door of the Florence Baptistery, which he won in a tie with the sculptor Lorenzo Ghiberti, but he refused to collaborate with him and left him in charge of the entire work. After this partial failure, he went to Rome with the sculptor Donatello: this was the first in a series of trips to the Eternal City, where he studied both ancient sculpture and architecture, especially from the point of view of building technique.

The construction of the dome of the Florentine Duomo (church of Santa Maria del Fiore) occupied almost the entire career of Brunelleschi, who was present on the site from 1404 until his death in 1446. The cathedral had been built beginning in 1296 to a design by Arnolfo di Cambio, but construction was halted at the height of the octagonal drum (the architectural structure on which the dome is set) because considerable technical and economic difficulties had prevented the great dome from being built.

In 1418 a competition was announced to gather ideas and construction proposals; Brunelleschi won it, and in 1420 construction of the dome began after he had produced the “device,” a twelve-point design program with instructions for workers, measurements and technical data. For the first time in the history of architecture, work was begun following a precise and detailed plan. The dome was completed in 1434, and two years later, Pope Eugene IV blessed the work.

Brunelleschi had the better of the other architects because he understood from the beginning that it was impossible to build the dome using the classic internal wooden reinforcement called cèntine. In fact, he proposed a dome, surmounted by a lantern, with two domes of stone and brick (one inner and one outer with different curvature and thickness that decreases as it proceeds upward), supported and reinforced by eight large stone ribs, each starting from the eight corners of the octagon of the tambour. Other smaller ribs inside the caps are connected to the outer eight by horizontal arches: to this primary structure are anchored the two brick caps, arranged in a technique known as “spinapesce”, which made it possible not to use traditional reinforcements since it was self-supporting, that is, able to support itself during construction without the help of other structures.

Brunelleschi always personally directed the construction site, sometimes clashing with the workers because he demanded that they follow his instructions and drawings to the letter. And just to better organise life on the building site, he had also designed a series of contraptions and wooden service bridges, which made it possible to bring food to the workers without them having to descend from the scaffolding.

But he did not hesitate to have those who did not follow his directions and instructions fired: the construction site depended directly on him, who assumed all responsibilities, both technical and organisational. Thus was realised the symbolic work of the Florentine Renaissance, born of the ingenuity of a single man but becoming emblematic of a city and an era.

Although the dome’s construction represented Brunelleschi’s most crucial and challenging commission, he carried out a prolonged architectural activity in parallel, designing many buildings, again in Florence. Before beginning the dome, the architect was already engaged in the design of the Ospedale Degli Innocenti, intended to house abandoned children: in the portico on the Piazza dell’Annunziata, for the first time, he introduced the proportional and harmonious relationships between individual building elements (columns, arches, windows) and used the materials that later became typical of Renaissance architecture, dividing the smooth white surfaces of the walls (plastered) with orders of pietra serena.

In the field of civil architecture, a series of Florentine palaces are attributed to him; these include the Palazzo Guelfo and the Palazzo Pitti, for which perhaps Brunelleschi drew the design for the first core, distinguished by the massive façade wall in which a succession of round arches opens, as in Roman aqueducts.

Geometrical and proportional modules were also used in the Old Sacristy of San Lorenzo, which was to serve as the Medici family’s aristocratic chapel: the room is perfectly cubic and is covered by a dome with ridges and sails, also called an umbrella dome, that is, formed by ribs and vaults; all the elements here, too, are of dimensions linked together by harmonic relationships.

In the chapel of the Pazzi family, located in the cloister of the church of Santa Croce, the design is based on the relationships derived from musical harmony. Still, in this case, the external facade on the cloister is also of great novelty, breaking away from the structure with its six Corinthian columns and wide central arch.

Of the numerous designs for sacred buildings, we are left with the churches of San Lorenzo and Santo Spirito. In the former, once again, the architect used proportional ratios to establish the dimensions in length, width, and height of the central nave and the two side aisles. In Santo Spirito, the interior measurements are organised by square modules, formed by the succession of columns and arches; here, Brunelleschi had planned a series of semicircular side chapels that were to protrude from the outer walls, but after his death, the protrusion was eliminated by flattening the wall.

In sacred buildings, chapels and churches, we see another key feature of Brunelleschian architecture: the rediscovery of the classical architectural order. Indeed, he employed the arch-column construction system following the model of Roman monuments, which he learned during his many study trips to Rome.

Brunelleschi had a profound influence on the architects of the second half of the 15th century; his innovative ideas, such as the invention of the perspective method and the resulting rational and proportional measurement of architectural space, would later serve Leon Battista Alberti in elaborating his treatises.