The Baptistery of San Giovanni is a major religious landmark of Pisa, located on the Field of Miracles and part of an architectural complex that also includes the Cathedral, the Leaning Tower of Pisa and the Campo Santo Cemetery. In 1986, the entire complex was listed as a UNESCO World Cultural Heritage Site.
Construction of the baptistery began in 1152 on the site of a pre-existing baptistery, and was completed in 1363. The architect of the building was Diotisalvi, whose initials and the date "1153" can be read on the two columns inside. The baptistery is 54.86 metres high and 107.24 metres in circumference - it is the largest baptistery in Italy. It is in an interesting transitional style - it shows features of both Romanesque (in the lower part with its circular arches) and Gothic styles (in the lancet arches of the upper level). The entire structure is made of marble, which is characteristic of Italian architecture.
The portal of the baptistery, facing the façade of the Cathedral of Pisa, is framed by two classical columns, and its internal vertical bars are in Byzantine style. The architrave is divided into two tiers: the lower one depicts episodes from the life of St John the Baptist, while the upper one shows Christ with the Madonna and John the Baptist surrounded by angels and evangelists.
The interior of the building is striking despite the lack of decoration. The octagonal font in the centre dates from 1246 - it was made by Guido Bigarelli da Como. And the bronze sculpture of John the Baptist in the centre of the font is the creation of Italo Griselli. Nicola Pisano, the father of Giovanni Pisano, who later made the pulpit for the Cathedral, worked on the preacher's pulpit from 1255 to 1260. The scenes with which the pulpit is decorated, especially the classical figure of the nude Hercules, are the best work of the sculptor, who became a forerunner of the Italian Renaissance.
Built on the same soft ground as the Tower of Pisa, the baptistery is inclined 0.6º towards the cathedral. The original shape of the structure, according to Diotisalvi's plan, was different. It may have been similar to the Pisan church of Santo Sepolcro with its pyramidal roof. After Diotisalvi's death, the work on the baptistery was continued by Nicola Pisano, who slightly changed the style. He also added an external roof in the form of a dome. This presence of two roofs, an inner pyramidal and an outer dome-shaped roof, created a marvellous acoustic inside the baptistery.
