In the counter-façade is a huge statue of Saint Romulus by Giovanni della Robbia (1521). The crypt's small columns have 11th century capitals, perhaps taken from the original construction. The decoration includes late Gothic medallions on the vault, while on the left wall is a cycle of the Stories of St. Romulus by the school of Domenico Ghirlandaio. The bishops' funerary chapel has a 13th-century icon attributed to one "Master of Bigallo", portraying the Madonna and Child (1215–1220).
