The Baptistery of San Giovanni sits below Siena Cathedral’s eastern end, its unfinished Gothic façade facing Piazza San Giovanni. Built in the early 14th century as part of the cathedral complex, it helped support the choir above. Its position below the Duomo makes it easy to overlook, but the interior is one of Siena’s great artistic treasures.
At the centre is a hexagonal baptismal font that brings together some of the finest sculptors of the early Renaissance. Gilded bronze reliefs by Lorenzo Ghiberti and Donatello depict scenes from the life of John the Baptist; Donatello’s Feast of Herod is especially striking for its dramatic perspective. Marble figures by Jacopo della Quercia adorn the font, while frescoes cover the vaults overhead.
From the cathedral, follow the building around its eastern end and descend the steps to the entrance. The historic centre is best explored on foot, though stairs and uneven paving can make access challenging. Allow 20–30 minutes to see the details, and consider visiting early or later in the day when the small space may be quieter. Combined cathedral-complex tickets often include the baptistery; check current opening hours and ticket options before visiting.