Baptistery of Neon
The oldest building in Ravenna is easy to miss: a plain octagon wedged between later houses, sunk a full storey below today's street level as the city's ground has slowly risen around it. It began as a Roman bath hall, converted to a baptistery around 430–450.
Inside, the dome mosaic shows Christ's baptism in the Jordan, personified river-god included, ringed by the twelve apostles processing around a jewelled throne. It is the first surviving example of this scene in monumental Christian art anywhere.
Unlike almost everything else this old in Europe, the font at its centre is still occasionally used for its original purpose — a baptistery that has never entirely stopped being one.
The Baptistery of Neon — also called the Neonian or Orthodox Baptistery, to distinguish it from the later Arian Baptistery across town — is Ravenna's oldest standing monument. Its brick core began as a Roman-era bath hall; it was converted into a baptistery attached to the city's original cathedral (itself since rebuilt) under Bishop Ursus around 400, then substantially redecorated under Bishop Neon in the mid-fifth century, whose name it now carries.
Centuries of accumulated street level around it mean the building now sits roughly a metre and a half below the surrounding piazza — an accident of urban geology that has, if anything, helped protect the structure by making it less convenient to alter or replace.
The dome mosaic is organised in three concentric registers. At the centre, Christ stands in the Jordan at his baptism, with John the Baptist to one side and a bearded, semi-nude personification of the river to the other — an unusually late survival of classical personification within an explicitly Christian scene. The middle register carries a procession of the twelve apostles bearing crowns of martyrdom toward a jewelled, empty throne prepared for Christ's return. The outer register alternates architectural thrones and altars, read by most scholars as a reference to the liturgical furniture of the room itself.
Restoration campaigns in the nineteenth and twentieth centuries repaired significant losses, particularly in the lower apostle register, and debate continues among specialists over how much of the surviving apostle mosaic is fifth-century versus later restoration matched to the original design — a caveat worth knowing before treating every figure as original fabric.
The building's continued liturgical use is unusual among monuments of this age: the octagonal font at its centre remains consecrated, and baptisms are still occasionally performed there, making it one of the very few fifth-century spaces in Europe that has never fully transitioned from active use to pure museum object.
