Events relating to religion
Theravada Buddhism, strong in south India and Sri Lanka, travels with traders through southeast Asia

Teotihuacan, the dominant city in the northern highlands of central America, introduces the god Quetzalcoatl
Buddhism, arriving with trade along the Silk Road from India, puts down firm roots in China
On the order of Marcus Aurelius, Christians in Lyons are tortured to death - an instance of persecution unusual at this time
Rabbi Judah ha-Nasi compiles the Mishnah, a six-part digest of the Oral Torah
A house in Doura-Europus is adapted for Christian worship - the earliest surviving example of its kind
Origen, living in Caesarea, compiles the Hexapla, displaying versions of the Old Testament in six columns for comparative study
The Persian prophet Mani establishes the dualistic Manichaean religion
The Christians of Rome use the catacombs as tomb chambers, and decorate the walls with murals on New Testament themes
Cyprian, bishop of Carthage, is one of many Christians martyred for refusing to sacrifice to the Roman gods
The emperor Aurelian, grateful for the apparent assistance of a Syrian sun god, establishes the cult of the Unconquered Sun - whose birthday is December 25
St Anthony, one of the early Christian hermits in the Egyptian desert, is tempted by terrifying hallucinations
The emperor Diocletian initiates a sustained persecution of Christians in the Roman empire

Constantine, preparing for battle against a rival at the Milvian Bridge, orders his men to wear a Christian symbol, the Chi-Rho, on their shields
After winning the battle at Milvian Bridge, Constantine marches into Rome and is formally acknowledged by the Senate as Augustus of the west

Constantine meets his co-emperor Licinius in Milan, and persuades him to follow a policy of encouraging the Christians
Warming to his new Christian role, Constantine summons more than 300 bishops to Arles to discuss the controversial issue of Donatus
Constantine founds several churches in Rome, among them the first St Peter's
Pachomius organizes in Egypt the first community of Christian monks, at Dandara on the Nile
Constantine convenes a council of 200 bishops at Nicaea to discuss the beliefs of Arius, which are deemed to be heresy
Helena, mother of the emperor Constantine, discovers in Jerusalem the cross on which Christ died - or so it is later claimed

Constantine's new Christian city on the site of Byzantium is inaugurated, as Constantinople

Constantine is at last baptized a Christian in Nicomedia, just a few days before his death
Frumentius, brought to Ethiopia as a slave, becomes the kingdom's first Christian bishop