Until Ascension Peter’s life was closely linked to that of Jesus. He was present at all important events. The embodyment of human strengths and weaknesses, Peter is the example of the struggle of faith and understanding that every disciple faces. Jesus clearly saw his disciples, at the Last Supper He predicted that Peter would deny Him three times (Matthew 26:31, 33, 34, 35). And He did not mistake.
After Crucifixion and Pentecost Peter became the head of the earliest Christian community in Jerusalem. He was imprisoned by Herod, but set free by an angel. In A.D. 44 he left for Rome, where he remained until his death, preaching, drawing together Christ’s disciples and organizing Church of Rome, of which he was the first bishop. He was crucified the same day as St. Paul beheaded; thinking himself unworthy to suffer the same fate as Jesus, he asked to be nailed to the cross upside down.
In fine arts St. Peter is often depicted with keys, cockerel, as the bird which heralded his betrayal of Christ (John 13:38), inverted cross, fishing boat, net, fish, chain, papal tiara. The key has a three-fold symbolic meaning: it indicates ownership and authority; it is a metaphor for a new life, the door to which it can open; and it represents a house. The key as an attribute of St. Peter includes all these meanings and derives from the Christ's words to St. Peter: "And I will give unto thee the keys of the kingdom of heaven: and whatsoever thou shalt bind on earth shall be bound in heaven: and whatsoever thou shalt loose on earth shall be loosed in heaven" (Matt. 16:19). Later the key became first a papal (who keep those keys) and then an ecclesiastical symbol.
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