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 Medici family. 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.
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.