The symbols seen here, of the anchor and the fish, were ones commonly used in context with Christianity. Examples have been found amongst the catacomb burial sites, on other intaglios and on personal amulets. The anchor is aesthetically similar to the crucifix and was a fitting symbol to be used when Christians wished to hide their faith. The fish, a well-known christian allegory, was called ‘Ichthys’ (Ιχθυς) in Greek. The word was an anagram for the phrase ‘Jesus Christ, Son of God, Saviour’, ‘Iēsous (Ἰησοῦς) Christos (Χριστός) Theou (Θεοῦ) uios (Υἱός) sōtēr (Σωτήρ)’. The first letter of every word making up the anagram.
This symbol seems to become less popular from the 4th century AD, however there were a few workshops in the Easter mediterranean that continued to produce engraved rings and gemstones with religious iconography into the 5th – 6th centuries.