The basilica was constructed in the 4th century, in 393CE, and dedicated to Saint Ambrogio. It was renovated in the Romanesque period, in 1059, and then rebuilt in the 15th century following a design created by Filippo Brunelleschi under the patronage of the Medici family.
While the basilica still maintains its role as a parish church it has been opened to a non-religious public as a museum in certain hours in order to allow a broader public to become familiar with the art and architecture inside.
Contributions to the church have been made by some of history's most significant artists and architects. The Old Sacristy, by Filippo Brunelleschi, dates to the 15th century and includes bas-reliefs by Donatello which recount stories from the life of Saint John the Evangelist. Donatello is also responsible for the Sacristy's bronze doors (15th century), and the pulpits with episodes from the lifes of Christ and Saint Lorenzo (15th century).
The tombs of Giovanni and Piero dei Medici by Andrea del Verrocchio, Rosso Fiorentino's altarpiece depicting the Marriage of the Virgin and a fresco by Bronzino showing the Martyrdom of Saint Lorenzo are also in the church's collection.