Inside the basilica, the eastern span of the Theodorian mosaic in the south hall is entirely occupied by episodes from the biblical story of Jonah.

The whole story represents an allegory of the resurrection of Christ, and more generally, of the otherworldly destiny that awaits those who have been baptized.

The three salient moments of the Old Testament saga are set within a marine context, populated by octopuses, cuttlefish, dolphins, ducks, and enlivened by fishing scenes.

To the north, the prophet is thrown into the sea from a boat and swallowed by a sea monster.

Towards the south, after the tondo with the celebratory inscription of Theodore, Jonah is rejected by the monster after three days, while in the following scene he is caught resting under a cucurbit plant.