This precious reliquary, by a Florentine goldsmith of the second quarter of the 15th century, contains eighteen links from the chains of St. Peter, donated in 1439 by Federico Chiaromonte, abbot of San Benedetto, to Santa Maria del Fiore. The reliquary is worked in silver, copper and bronze, and takes the form of urn with trapezoidal lid, resting on lion feet. At the corners are statuettes of angels in the round.

This relic of the chain refers to the Gospel episode (Acts of the Apostles) of Peter's imprisonment in Rome, from which he miraculously escaped, assisted by an angel. This story is also given precise reference by the angel statuettes.