The Medici Chapel is the New Sacristy built onto the church of San Lorenzo in Florence and in plan balances the Old Sacristy by Brunelleschi. It was commenced around 1491 and work was continued by Michelangelo in the periods 1520-1524 and 1530-1533, although he left it incomplete. It is built from dark Istrian stone (pietra serena) and white marble and is lit only from above. It was used from the outset as a funerary chapel for the Medici with the severe architecture providing a setting for the famous Medici tombs. Michelangelo executed two of these, the first of which has on the sarcophagus reclining figures of Dawn and Dusk, matched by similar figures of Day and Night on the second. It is to these that Ruskin refers.