Inside the church you can admire some splendid wall paintings by Filippo di Antonio Filippelli including the 1484 Martyrdom of St. Sebastian, which Bernardo Rosselli also worked on. Not to be missed is the oldest chivalric tomb in Tuscany, namely the tomb slab of Gherarduccio Gherardini who died in 1331, ancestor of the Monnalisa.
On the outside, the four supporting pillars of the Baptistery, which was located in front of the church facade and had an octagonal shape, remain. Very distinctive are the decorations on the capitals depicting the tau, cosmic signs and the cross.
On the adjacent premises is the Antiquarium, which collects some of the archaeological material found in the surrounding area. It is a small museum that preserves alabaster funerary urns from the Hellenistic period, red-figure Attic ceramics and a range of late medieval and Renaissance ceramics typical of the Florentine area, as well as some Etruscan memorial stones and a pagan idol.