The Battistero San Giovanni, or Baptistery of St John the Baptist, was finished in the early twelth century, built on the site of an early fifth century baptistery.
Common for early Christian baptisteries the octagonal shape symbolizes the six days of creation, a day of rest, plus a Judgement Day. On this Day believers sought resurrection and the promise of Heaven through the sacrament of Baptism.
The baptistery is renowned for three sets of double bronze doors adorned with panels of biblical scenes sculpted by Andrea Pisano and Lorenzo Ghiberti, and over 1,000 square meters of mosaics with the theme Christ as Judge covering the dome ceiling.
Above the altar on the west side is a Last Judgement scene with Christ at center surrounded by seven tiers, or registers, depicting fifteen biblical stories each of Christ, Joseph the Hebrew, John the Baptist and the Book of Genesis, with choirs of Angels, the Apostles with Mary and John the Baptist, and scenes of resurrection of the saved and the damned.