The baptistery drum, with its one side of distinctive black-and-white marble bands, was built in 1283, but the dome was added in the 16th century. Just inside the door is an Etruscan funerary urn recycled as a holy water stoup, and in the center is an 18th-century font. This polychrome affair replaced the smaller, more elegant marble font Andrea Sansovino carved with simple reliefs in 1502, now against the right wall.