Exterior view

In the 1480s Lorenzo de' Medici selected Giuliano to design not only the buildings he commissioned directly (the Villa Medici at Poggio a Caiano and San Gallo, Florence) but also others on which he had a decisive influence (Santa Maria delle Carceri, Prato; the sacristy of Santo Spirito, Florence). In addition, Giuliano was one of the agents of Lorenzo's cultural diplomacy. At Lorenzo's death in 1492, Giuliano was engaged on at least four building projects for him.

The church of Santa Maria delle Carceri in Prato is one of the jewels of Renaissance architecture. It was a votive church, commemorating a miracle-working image in the city prisons. The name, "Carceri," which means "prison" in Italian, reflects the painting's location on the outer wall of a prison.

After an architectural competition, a project by da Maiano family had been chosen in 1484, but Lorenzo de' Medici is said to have intervened to impose Sangallo, who then both supplied the wooden model and supervised construction from 1485 to 1499.

The Greek cross ground-plan has entrances on three sides. The simple mathematical proportions and the interior spaces crowned with an umbrella dome on pendentives are strongly reminiscent of Brunelleschi. Giuliano's loyalty to the latter is documented in a letter of 1486, in which he begged Lorenzo de' Medici to intervene at Santo Spirito to restore Brunelleschi's four-door solution for the façade. Wholly characteristic of Giuliano, however, is the treatment of the decorative detail at Santa Maria delle Carceri. The pilaster capitals are inventive variants on the Pegasus capitals of the temple of Mars Ultor, Rome, with the volutes being replaced by winged symbols of the four evangelists, while the exuberant central foliage is shaped into the fleur-de-lis of Prato's civic insignia.

The green and white marble cladding of the exterior is unfinished, only the lower storey being executed in Giuliano's time. Typical also of Giuliano is the use of balustrades, both at the base of the drum inside and outside around the lantern.

View the ground plan of the church.