one of the oldest monuments in the city, in simple brick on the outside but rich in marble, stucco and mosaics with a clear Hellenistic-Roman influence on the inside. Dominating the dome, commissioned by Bishop Neone in the mid-fifth century, is the scene of the Baptism of Christ surrounded by a very refined procession of the twelve Apostles that stands out against a brilliant background of blue tesserae. Inside there is still the baptismal font from the Renaissance period, which takes up the octagonal shape of the Baptistery plan and which preserves the ambo from the 5th century.