Earliest account of Peter's death (AD 80 - 140)

But let us pass from ancient examples, and come unto those who have in the times nearest to us, wrestled for the faith. Let us take the noble examples of our own generation. Through jealousy and envy the greatest and most just pillars of the Church were persecuted, and came even unto death. Let us place before our eyes the good Apostles. Peter, through unjust envy, endured not one or two but many labours, and at last, having delivered his testimony, departed unto the place of glory due to him. Through envy Paul, too, showed by example the prize that is given to patience: seven times was he cast into chains; he was banished; he was stoned; having become a herald, both in the East and in the West, he obtained the noble renown due to his faith; and having preached righteousness to the whole world, and having come to the extremity of the West, and having borne witness before rulers, he departed at length out of the world, and went to the holy place, having become the greatest example of patience. ~ 1 Clement 5

1 Clement and the phoenix

Let us consider that wonderful sign [of the resurrection] which takes place in Eastern lands, that is, in Arabia and the countries round about. There is a certain bird which is called a phoenix. This is the only one of its kind, and lives five hundred years. And when the time of its dissolution draws near that it must die, it builds itself a nest of frankincense, and myrrh, and other spices, into which, when the time is fulfilled, it enters and dies. But as the flesh decays a certain kind of worm is produced, which, being nourished by the juices of the dead bird, brings forth feathers. Then, when it has acquired strength, it takes up that nest in which are the bones of its parent, and bearing these it passes from the land of Arabia into Egypt, to the city called Heliopolis. And, in open day, flying in the sight of all men, it places them on the altar of the sun, and having done this, hastens back to its former abode. The priests then inspect the registers of the dates, and find that it has returned exactly as the five hundredth year was completed. [1]

~ 1 Clement 25