The Baptistery of Neon is a relic of the final years of the Roman Empire, when the seat of the western government was Ravenna. Erected in the early fifth century on the site of a previous Roman bath, the baptistry was originally connected to a great basilica called the Church of the Anastasis, which was destroyed in the 18th century. The baptistery's mosaics were updated by a certain Bishop Neon (hence the name) in the 470s, freshened up just in time for the city to fall to the Goths in 476.

The center of the colorful cupola shows John the Baptist baptizing Jesus in the River Jordan, represented on the right by a gray-bearded man. The subsequent ring shows a procession of the 12 apostles led by Saints Peter and Paul; the farther ring displays empty thrones, heavenly gardens, altars with Gospel books, and seats surrounding the altars reserved for the elect. The arches feature prophets and biblical stories.

The mosaics in the cupola of the nearby Arian Baptistry, built several decades later, draw clear inspiration from the Baptistry of Neon, right down to the anthropomorphized River Jordan. Scholars have remarked that the mosaic work of the former is not of the standard of Neon's, a testament to the fact that only a few years after the fall of Rome the knowledge of ancient crafts was deteriorating.

Psychoanalyst Carl Jung was enchanted by the mosaics of Ravenna, particularly those of the Baptistry of Neon and the nearby Tomb of Galla Placidia, to the point where he reported an uncanny experience connected to them. He and a friend recalled witnessing several mosaics, including one of Jesus pulling Peter from the Sea of Galilee, that he later discovered do not exist. Jung later wrote, "The very walls of the baptistry, that my physical eyes necessarily saw were covered and transformed by a vision that was equally true as the unchanged baptismal font. What was actually real in that moment?"