Tondo in glazed and polychrome terracotta, depicting the Agnus Dei in a wreath of fruits is atributed to Andrea della Robbia’s workshop and dated 1486. It served as an ornament to the keystone of the ceiling of some room of the Opera. The tondo portrays the Agnus Dei, symbol of  Santa Maria del Fiore and of Wool Merchants’ Guild of Florence, the powerful corporation that had been the Opera’s patron since 1331. The lamb with the halo and the cross banner is also a symbolic reference to Christ, often referred to in the New Testament as “Lamb of God, who takes away the sins of the world”, for example by John the Baptist when he speaks of the redemption achieved by the sacrifice of Christ on the cross, or by John the Evangelist who sees him rise again during the Apocalypse in the Book of Revelation.