Basilica di San Lorenzo

The Basilica di San Lorenzo (Basilica of St Lawrence) is one of the largest churches of Florence, Italy, situated at the centre of the city’s main market district, and the burial place of all the principal members of the Medici family from Cosimo il Vecchio to Cosimo III. It is one of several churches that claim to be the oldest in Florence; when it was consecrated in 393 it stood outside the city walls. For three hundred years it was the city's cathedral before the official seat of the bishop was transferred to Santa Reparata. San Lorenzo was also the parish church of the Medicifamily. In 1419, Giovanni di Bicci de' Medici offered to finance a new church to replace the 11th-century Romanesque rebuilding. Filippo Brunelleschi, the leading Renaissance architect of the first half of the 15th century, was commissioned to design it, but the building, with alterations, was not completed until after his death. The church is part of a larger monastic complex that contains other important architectural and artistic works: the Old Sacristy by Brunelleschi, with interior decoration and sculpture by Donatello; the Laurentian Library by Michelangelo; the New Sacristy based on Michelangelo's designs; and the Medici Chapels by Matteo Nigetti.

Though considered a milestone in the development of Renaissance architecture, S. Lorenzo has a complicated building history. Even though it was built – at least partially - under the direction of Filippo Brunelleschi, it is not purely of his design. The project was begun around 1419, but lack of funding slowed down the construction and forced changes to the original design. By the early 1440s, only the sacristy (now called the Old Sacristy) had been worked on as that and the church was being paid for by the Medici. In 1442, the Medici stepped in to take over financial responsibility of the church as well. Brunelleschi died, however, in 1446 and the job was handed over either to Antonio Manetti or to Michelozzo; scholars are not certain. Though the building was “completed” in 1459 in time for a visit to Florence by Pius II, the chapels along the right-hand aisles were still being built in the 1480s and 1490s.

By the time the building was done, many aspects of its layout, not to mention detailing, no longer corresponded to the original plan. The principal difference is that Brunelleschi had envisioned the chapels along the side aisles to be deeper, and to be much like the chapels in the transept, the only part of the building that is known to have been designed by Brunelleschi.

Despite its history, the building is seen as one of the great examples of the new style. Its more notable features include:

• the attempt to create a proportional relationship between nave and aisle (aisle bays are square whereas nave bays are 2X1).
• the articulation of the structure in pietra serena (Italian: “dark stone”).
• the use of an integrated system of column, arches, entablatures.
• a clear relationship between column and pilaster, the latter meant to be read as a type of embedded pier.
• the use of proper proportions for the height of the columns
• the use of spherical segments in the vaults of the side aisles.

There are significant problems in the design, most, however, occur at the level of detail. Already Giorgio Vasari thought that the columns along the nave should have been elevated on plinths. That the pilasters along the wall of the side aisles rest on a floor that is three steps higher than the nave, is also considered an error.

San Lorenzo is often compared with Santo Spirito, also in Florence. Santo Spirito, which Brunelleschi began somewhat later, is considered to have been constructed more or less in conformity with his ideas, even though Brunelleschi died before most of it was built.

The Medici Pope Leo X gave Michelangelo the commission to design a façade in white Carrara marble in 1518. Michelangelo made a wooden model, which shows how he adjusted the classical proportions of the facade, drawn to scale, after the ideal proportions of the human body, to the greater height of the nave. The work remained unbuilt. Michelangelo did, however, design and build the internal facade, seen from the nave looking back toward the entrances. It comprises three doors between two pilasters with garlands of oak and laurel and a balcony on two Corinthian columns.

In recent years, the association of “Friends of the Elettrice Palatina” and the Comune of Florence re-visited the question of completing the outer facade according to Michelangelo's designs. To assist with the public debate, a computerized reconstruction was projected onto the plain brick facade in February 2007. As yet, no decision has been made on the project.

The campanile dates from 1740.

Old Sacristy

Opening off the north transept is the square, domed space, the Sagrestia Vecchia, or Old Sacristy, that was designed by Brunelleschi and that is the oldest part of the present church and the only part completed in Brunelleschi's lifetime; it contains the tombs of several members of the Medici family. It was composed of a sphere on top of a cube; the cube acting as the human world and the sphere the heavens.

New Sacristy

Opposite it in the south transept is the Sagrestia Nuova (New Sacristy), begun in 1520 by Michelangelo, who also designed the Medici tombs within. The new sacristy was composed of three registers, the topmost topped by a coffered pendentive dome. The articulation of the interior walls can be described as early examples of Renaissance Mannerism (see Michelangelo's Ricetto in the Laurentian Library). The combination of pietra serena pilasters on the lower register is carried through to the second; however, in Mannerist fashion, architectural elements 'seem impossible,' creating suspense and tension that is evident in this example. Michelangelo's sculptural elements, to be used on the tombs themselves, was left undone. A difficult person to work with, Michelangelo refused to direct the completion of the new sacristy.