In the Cathedral of San Cerbone, the Baptismal Font is carved from a single block of travertine and dates from 1267. It was executed by Como, Giroldo (di Jacopo) [ also known as da Giroldo da Lugano] who was active in the period 1267-74. There are works by him in other parts of Tuscany: San Miniato in the Cathedral, the Duomo in Carrara, at Badia di S. Maria near Montepiano,and at Volterra in the Baptistry.
Three sides of the font depict scenes from the life of St John the Baptist. The fourth represents his Glorification.
Of note is the use of Greek characters on the font. Massa had contacts with the Far East through its trade links. Another source of Greek learning was the presence in Massa of Irish influence through Simone l'Irlandese.
Originally, when built, baptism was by immersion.
The marble Tabernacle balancing above it dates back to the year 1447 and is decorated according to the criteria of the “Medieval Bestiaries”, with scenes from the Bible and the Gospels. On top is a statue of St John the Baptist.
Amongst those baptised at the font was Saint Bernardino of Siena (September 8, 1380 – May 20, 1444) the Italian preacher, Franciscan missionary and Christian saint. Bernardino was born in 1380 to the noble Albizeschi family in Massa Marittima, of which his father was then governor.