There is little biographical information about Brunelleschi’s life to explain his transition from goldsmith to architect and, no less importantly, from his training in the gothic or medieval manner to the new classicism in architecture and urbanism that we now loosely call the Renaissance and of which Brunelleschi is considered the seminal figure. By 1400 there emerged an interest in humanitas which contrasted with the formalism of the medieval period, but initially this new interest in Roman antiquity was restricted to a few scholars, writers and philosophers; it did not at first influence the visual arts. Apparently it was in this period (1402–1404) that Brunelleschi and his friend Donatello visited Rome to study the ancient Roman ruins. Donatello, like Brunelleschi, had received his training in a goldsmith’s workshop, and had then worked in Ghiberti’s studio. Although in previous decades the writers and philosophers had discussed the glories of Ancient Rome, it seems that until Brunelleschi and Donatello made their journey, no-one had studied the physical fabric of these ruins in any great detail. They gained inspiration too from ancient Roman authors, especially Vitruvius whose De Architectura provided an intellectual framework for the standing structures still visible.

Brunelleschi’s first architectural commission was the Ospedale degli Innocenti (1419–ca.1445), or Foundling Hospital. Its long loggia would have been a rare sight in the tight and curving streets of Florence, not to mention its impressive arches, each about 8 meters high. The building was dignified and sober; there were no displays of fine marble or decorative inlays. It was also the first building in Florence to make clear reference—in its columns and capitals—to classical antiquity.

Soon other commissions came, such as the Ridolfi Chapel in the church of San Jacopo sopr’Arno, now lost, and the Barbadori Chapel in Santa Trinita, also modified since its building. For both, Brunelleschi devised elements already used in the Ospedale degli Innocenti, and which would also be used in the Pazzi Chapel and the Sagrestia Vecchia. At the same time he was using such smaller works as a sort of feasibility study for his most famous work, the dome of the Cathedral of Florence.

Florence Cathedral
Santa Maria del Fiore was the new cathedral of the city, and by 1418 the dome had yet to be defined. When the building was designed in the previous century, no one had any idea how such a dome was to be built, given that it was to be even larger than the Pantheon’s dome in Rome and that no dome of that size had been built since antiquity. Because buttresses were forbidden by the city fathers, and because it was impossible to obtain rafters for scaffolding long and strong enough (and in sufficient quantity) for the task, it was unclear how a dome of that size could be constructed without it collapsing under its own weight. Also, the stresses of compression were not clearly understood, and the mortars used in the period would set only after several days, keeping the strain on the scaffolding for a very long time.

In 1418, the Arte della Lana, the wool merchants’ guild, held a competition to solve the problem. The two main competitors were Ghiberti and Brunelleschi, with Brunelleschi winning and receiving the commission. The competition consisted of the great architects attempting to stand an egg upright on a piece of marble. None could do it but Brunelleschi, who, according to Vasari:“… giving one end a blow on the flat piece of marble, made it stand upright …The architects protested that they could have done the same; but Filippo answered, laughing, that they could have made the dome, if they had seen his design.”

The dome, the lantern (built 1446–ca.1461) and the exedra (built 1439-1445) would occupy most of Brunelleschi’s life.[14] Brunelleschi’s success can be attributed, in no small degree, to his technical and mathematical genius.Brunelleschi used more than four million bricks in the construction of the dome. He invented a new hoisting machine for raising the masonry needed for the dome, a task no doubt inspired by republication of Vitruvius’ De Architectura, which describes Roman machines used in the 1st century AD to build large structures such as the Pantheon and the Baths of Diocletian, structures still standing which he would have seen for himself. He also issued one of the first patents for the hoist in an attempt to prevent the theft of his ideas. Brunelleschi was granted the first modern patent for his invention of a river transport vessel.

Brunelleschi kept his workers up in the building during their breaks and brought food and diluted wine, similar to that given to pregnant women at the time, up to them. He felt the trip up and down the hundreds of stairs would exhaust them and reduce their productivity.