Neonian Baptistery (also known as Orthodox) dates back to the 5th century and is named after Bishop Neone, who continued its construction after his predecessor Orso. It has octagonal shape in the plant, according to the numerology that associates the eight resurrection wing (sum of 7, time + 1, God). Externally it has a simple clay coating, from which four apts added in the 10th century. The interior stands out for the decoration of the mosaic dome. Within three concentric rings there are several subjects: in central round, on a gold background, is the scene of Jesus' Baptism. The marble baptismal bathtub placed in the center of the building is also octagonal and dates back to the 16th century.
The Baptistery is recognized by UNESCO World Heritage List, inserted in serial track "Paleochristian Monuments of Ravenna".