The construction of the "Battistero di San Giovanni" started in 1152 to replace an older baptistry. Since its completion in 1363 the transition from (Pisan) Romanesque to (Pisan) Gothic style was visible.

The baptistry was designed by Diotisalvi, who signed and dated the building ("1153"), similar to the "Chiesa del Santo Sepolcro" (previous uploads), he had designed some decades before.

The baptistry is about 54 m high, with a circumference of 107 m.

The two level lintel of the central portal depicts the life of St. John the Baptist and above Christ with Mary, John the Baptist, the Evangelists and angels. The outer archivolt depicts the "Elders of the Apocalypse".