The Basilica di San Lorenzo 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, having been consecrated in 393, at which time 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 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.