Florentine architect, the first and perhaps the most distinguished of the Renaissance, who trained as a sculptor and goldsmith, learned geometry, and developed the laws and principles of perspective. Gradually he became more interested in architecture, and from 1417 advised on the proposed cupola for the Cathedral of Santa Maria del Fiore, Florence. His inspiration for his architecture was certainly from earlier buildings, but it came from the Tuscan Romanesque and proto-Renaissance buildings rather than from the remains of Imperial Roman architecture, for structures such as San Miniato al Monte and the baptistery, Florence (both C11 and C12), were thought at the time to be much older than they were. Indeed, he was less of an antiquarian than those who followed him, notably Alberti and Michelozzo, and seems to have been more interested in the problems of construction, definition of architectural elements by linear means, and the control and management of volume. In 1420 he began to build the Cathedral cupola (in collaboration with Ghiberti), a vast octagonal structure crowned by an enormous lantern designed by Brunelleschi alone (1436–67). The octagon, double shell, and pointed profile were settled before Brunelleschi's involvement, but the use of spiralling courses of herringbone brickwork, iron chains and sloping masonry rings to bind the dome together, and ribs joining the shells are his inventions, although owe much to his studies of Roman structures. Brunelleschi's genius lay in his abilities to combine ancient and modern aesthetic, architectural, and engineering principles.
His Ospedale degli Innocenti (Hospice for the Innocents, or Foundlings' Hospital), Florence (1419–44), with its elegant arcades on Corinthian columns, glazed terracotta medallions in the spandrels, architrave dividing first and second floors, and small rectangular windows over which are pediments, is reckoned to be the very first truly Renaissance building, but its sources are local. Brunelleschi designed two basilican churches (San Lorenzo (from 1418) and Santo Spirito (from 1436): both have nave-arcades with Classical columns carrying fragmentary entablatures from which the arches spring, and both have domed crossings with transepts, although at Santo Spirito the aisles and semicircular side-chapels carried all round the church give a rhythmic unity not present at San Lorenzo. At the latter Brunelleschi designed the Old Sacristy, also the Mortuary Chapel of the Medicis, as a cube roofed by a dome with ribs radiating from the central lantern giving an impression of sail-like forms over ribs. The entire interior was painted white with bands of grey on the dominant architectural motifs, the first time such a decorative scheme was employed. Brunelleschi may have designed the Pazzi Chapel in the cloister of Santa Croce, Florence (1429–61), where the Old Sacristy themes are developed with a central domed space flanked on two sides by barrel-vaulted side bays and on the third by a small domed recess set behind an arch. The chapel is approached through an entrance-loggia consisting of two groups of three Corinthian columns carrying an entablature between which is an arch. Behind the arch is a saucerdome. The fine interior is articulated by means of pilasters, entablatures, archivolts, and other architectural elements, all in local grey stone (pietra serena), set against the white walls, while glazed terracotta roundels complete the scheme.