Cf. Sarcophagus of Archbishop Theodore, Basilica of St Apollinaris in Classe in Ravenna for a similar scene of birds either side of a cross atop a cantharus and dating to the late 7th Century.
The peacock was an important symbol in the early Christian period. It was believed that the flesh of a peacock did not decay after death, thereby rendering it somewhat immortal, and akin to Christ. In addition, the bird was also associated with the Resurrection as it annually sheds its feathers and grows newer, brighter. Lastly, eye-like markings upon its tail-fan, as seen here, were associated with the all-seeing eye of God. The cantharus, a Dionysiac drinking vessel in the Graeco-Roman period, later became the receptacle for the "water of life". The grape vine, again once with strong Dionysiac associations, could be related to the wine of the Eucharist, and thus once again everlasting life; 'I am the vine; you are the branches' (Christ, John 15:5).