A serpent. This may seem strange as a Christian symbol, but it denotes foresight, and recalls the Gospel monition, “Be ye wise as serpents and harmless as doves.” A Christian gem evidences this interpretation, for on either side of the serpent is figured a dove. The vine; suggested by the words of Christ: “I am the vine and ye are the branches.” A blade of wheat. The harvest of souls? The symbolic design of a ship traversing the sea was used in early Christian funeral sculptures, and also in pagan Rome, to denote the course of life. For the Christians the tempest-tossed vessel of life found its port and resting place in death. This idea is rudely figured in a design on a sepulchral stone, in memory of a certain Firmia Victoria, from one of the early Christian cemeteries of Rome. On it appears a ship riding the waves, and in the background a four-storied tower from which rises a flame, the lighthouse marking the final port toward which the vessel bends its course.[406] Of the few designs engraved upon Græco-Roman rings which were permitted to the early Christians, the dove, as has been noted, symbolized the Holy Spirit; a fish became a Christian symbol because the Greek word for fish (_ichthus_) gave the initial letters of Iesus Christos, Theou huios, Soter (Jesus Christ, The Son of God, the Saviour). An anchor, or the representation of a fisherman, recalls to mind the Fisherman’s Ring of the Roman pontiff. The fish symbol appears on an engraved Gnostic gem bearing the head of Christ surrounded with the Greek letters of his name. This offers one of the types current in the third and fourth Christian centuries. We have the testimony of St. Augustine that the diversity of types in his time was very great, and that no record remained of what Christ’s physical appearance really was.[407] The oldest portrait is believed to be that on the ceiling of a chapel in the cemetery of St. Calixtus at Rome, and the type presented here is that which has persisted essentially to the present day. The ring of the Christian martyr Saturus was a precious memorial of his death for the faith. When he had already received his death-blow, he took off his ring and moistening it with the blood that was flowing from his wound, handed it to the Roman soldier, Pudeus, who was present at his death, but was a secret convert to the Christian faith, charging the soldier to guard it as a heritage and a reminder that true faith was rather confirmed than weakened by the martyr’s death.[408]