Outside, the round exterior arches built in the Romanesque style, date from the 11th Century. The door facing south was created by Andrea Pisano, with the north and east facing doors having been created by Lorenzo Ghiberti.
The Battistero di San Giovanni or The Baptistery of St. John can be accessed from both the Piazza di San Giovanni and the Piazza del Duomo. This octagonal shaped building with its cladding of white and green marble is a popular tourist attraction, so visitors would be advised to visit in the early morning as it can become very busy further on in the day. The Battistero is believed to be one of Florence's oldest buildings and evidence suggests it was built on the site of a much older Roman building which dated back as far as the 1st century, although none of this original building is evident today, with most of which that can now seen having been created between the 11th and 14th centuries.
The eastern door is known as the Gates of Paradise. The door is in fact a copy, the original was removed for restoration, now fully restored, the panels are on display in the Museo dell´Opera del Duomo. It is claimed that the doors were given their name when Michelangelo was so taken back by their beauty he claimed they could serve as the Gates of Paradise. The ten panels depict, Adam and Eve, Cain and Abel, The drunkenness of Noah, Abraham and Isaac, Esau and Jacob, Joseph being sold into slavery, Moses and the ten commandments, The fall of Jericho, David and Goliath, and finally, king Solomon and the queen of Sheba. The marble sculpture above the door is named The Baptism of Christ, and was crafted by Andrea Sansovino. Again the sculpture now on display is a copy, with the original in the Museo dell´Opera del Duomo.
The interior of the Battistero or Baptistry is reminiscent of the Pantheon in Rome. The lower part is ringed with columns of Sardinian granite. In the latter half of the 11th century, work commenced to clad the walls with dark green and white marble, in a geometric pattern. The marble floor, again in a geometric pattern was started in 1209, with the rectangular apse being faced with mosaics in 1225. The Baptistry contains the tomb of Antipope John XXIII which is adorned with a gilt statue supported by two lions.
The ceiling is covered with magnificent mosaics with the earliest thought to date back to 1225, but with the work as we see it today, not being completed until the 14th century. Above the high alter is the mosaic of the last judgment depicting Christ with the Angels of Judgment. Other mosaics depict scenes such as Choirs of Angels, stories from the Book of Genesis, Mary and Christ, and very suitable for a baptistery, Saint John the Baptist.