The catacombs of St. Callixtus are among the greatest and most important of Rome. They originated about the middle of the second century and are part of a cemeterial complex which occupies an area of 90 acres, with a network of galleries about 12 miles long, in four levels, more than twenty meters deep. They are named after the deacon Callixtus who, at the beginning of the third century, was appointed by pope Zephyrinus as the administrator of the cemetery and so the catacombs of St. Callixtus became the official cemetery of the Church of Rome. The image at the top right is the earliest visual representation of Jesus, portrayed as a beardless young man returning a lost sheep to the flock. It dates from around 200 AD. Other renditions of the same theme are frequently found in these burial vaults. The carved sarcophagus (middle) dates from the 4th century, and the splendid mosaic (bottom) dates from the fifth.
THE CHURCH AND THE EMPIRE
The first officially-sponsored persecution of the Church, as noted earlier, occurred during the reign of Nero, around 64 AD. Tradition maintains that Nero had found that burning Christians provided an excellent source of illumination for his late-night garden parties. The persecution intensified under Domitian, who reigned from 81 until 96 AD, due to a renewed emphasis upon Emperor-worship throughout the Empire. Christians, for the most part refused, and as a result were executed. In all likelihood it was during the reign of Domitian that the book of Revelation, also known as the Apocalypse, was written to encourage those being oppressed for their faith.
Under Caracalla (211-217) the persecution lessened, due primarily to his extension of citizenship to everyone within the Empire. A Roman Citizen had the automatic right to appeal, and large numbers of death sentences would impair the legal system beyond all remedy. However, the eleven years between 249 and 260 constituted virtually upon Christianity as the Emperors Decius and Valerian attempted to destroy the Church
For almost a generation, from 260 until 303, the Church ceased to be the target of Roman aggression, and historians of the Church have given this period the title "The Long Peace." Persecution was restored in 303 under Diocletion and intensified under Galerius, but Galerius was not the type of man to leave his bases uncovered, and in 311 the dying Emperor acknowledged defeat and sought the prayers of the Christians.
The Roman persecution of Christians came to an end in 313, when the Emperor Constantine converted to Christianity. The Emperor Constantine had led his forces to a confrontation with Maxentius, and he was alarmed by reports that the latter had mastered some sort of magical forces with which to defeat Constantine. Constantine therefore sought the aid of the unknown Supreme God in prayer, and as a result he saw a cross in the noonday sky above the sun, and heard the words In Hoc Signo Vinces, a Latin phrase meaning "In this Sign Conquer."
The ability of a religious doctrine based on peace and passivity, within three centuries, to triumph over the supreme secular power of its age is perhaps the most impressive event in human history.