In the meantime, the number of the Christians being now very large, it happened that Rome was destroyed by fire, while Nero was stationed at Antium. But the opinion of all cast the odium of causing the fire upon the emperor, and he was believed in this way to have sought for the glory of building a new city. And in fact, Nero could not by any means he tried escape from the charge that the fire had been caused by his orders. He therefore turned the accusation against the Christians, and the most cruel tortures were accordingly inflicted upon the innocent.
Nay, even new kinds of death were invented, so that, being covered in the skins of wild beasts, they perished by being devoured by dogs, while many were crucified or slain by fire, and not a few were set apart for this purpose, that, when the day came to a close, they should be consumed to serve for light during the night. In this way, cruelty first began to be manifested against the Christians. Afterwards, too, their religion was prohibited by laws which were enacted; and by edicts openly set forth it was proclaimed unlawful to be a Christian.
At that time Paul and Peter were condemned to death, the former being beheaded with a sword, while Peter suffered crucifixion. And while these things went on at Rome, the Jews, not able to endure the injuries they suffered under the rule of Festus Florus, began to rebel. Vespasian, being sent by Nero against them, with proconsular power, defeated them in numerous important battles, and compelled them to flee within the walls of Jerusalem. In the meanwhile Nero, now hateful even to himself from a consciousness of his crimes, disappears from among men, leaving it uncertain whether or not he had laid violent hands upon himself: certainly his body was never found.
It was accordingly believed that, even if he did put an end to himself with a sword, his wound was cured, and his life preserved, according to that which was written regarding him—“And his mortal wound was healed,”— to be sent forth again near the end of the world, in order that he may practice the mystery of iniquity.
Source: Sacred History (New Advent)