The Baptistery of San Giovanni, built in the second half of the thirteenth century, stands in front of Volterra Cathedral and is characterized by its massive appearance and octagonal plan with a domed finish. Clad in green and white marble bands on the side facing the cathedral, it features a Romanesque portal that documents the presence in Volterra of a master who found obvious inspiration in Nicola Pisano. The capitals of the pillar columns and jambs are carved with motifs of acanthus leaves, animal figures, and human heads. Completing the facade is a single lancet window and, in the architrave, Heads of Jesus, Mary, and the Apostles.
Inside, six niches and eight single-lancet windows punctuate a space whose early 16th-century dome does not match the columns placed at the corners of the octagon. In addition to the stoup carved from an Etruscan cippus that appears on the right side, the interior of the Baptistery holds some significant 16th-century works: the altar sculptures, designed and decorated by Mino da Fiesole and executed by Jacopo and Franco di Alessandro Balsimelli da Settignano (1500), the panel painting representing the Ascension, by Nicolò Cercignani da Pomarance (1591), placed above the altar. And, in the niche to the right, an ancient baptismal font by Andrea Sansovino (1502) is preserved: the five marble reliefs decorating it represent Faith, Hope, Charity, the Baptism of Christ and Justice. The later and more impressive baptismal font that stands out in the center is by Giovanni Vaccà (1759).
