Long,Long ago....the baptistry was a pagan temple, before it too, was converted around the 5th century. The octagon shape symbolizes the " eigth day". Since Genesis in the Bible addresses the 7 days of cretion, the eigth day is the time of the Risen Christ....or beyond the scope of human time.
Originally a cemetery surrounded this building, which must have been very impressive in the theme of death and resurrection as well as salvation through baptism.
The famous bronze doors (- the oldest ones on the south side show the life of St. John & were created by Pisano in 1330. The Ghiberti doors are on the East and North. The East doors were called the " gates of Paradise" by Michelangelo while the North doors show the new testament -) are fabulous copies, while the originals are kept safe in the museum.
The interior of the building is a cross-combination of ancient Greek, Roman, Islamic, and Germanic styles indicating that this place is the center of the religious world. The mosaics will leave you speachless! The Risen Christ is a huge focal point with the dead rising from their coffins under his feet. To the right, you will see the damned being thrown into hell and being devoured in the mouth of the devil. Pretty impressive as well as gross!
Regroup your thoughts looking further down the dome to the creation of the world and the garden of Eden as the bible unfolds above you. Above these rows are the Angels of GOD who watch over all of us, while in the center of the room is the great light--symbol of GOD HIMSELF.
You might ask me...who is the guy buried in the wall here? Well, it's another interesting story! He was an Antipope. It's kind of a long story about fighting within the church itself...like where should the center of the church be? Rome, Constantinople, France??? Over 30 Antipopes arose to be called the "Illegal Pretenders" who weren't rightfully elected by canon law. This was an ugly thing that caused many splits within the church. I'm not sure which one this guy is....probably GregoryV1 or ClementV11. It's more important to know that this division occured.