Ancient World
Diocletian and the Tetrarchy (293): Rule of Four Emperors
The Tetrarchy stabilised the empire after the third-century crisis, but the succession plan broke down soon after Diocletian abdicated in 305.
Era · c. 3000 BC – AD 500
Ancient World
The first cities, empires and written records, from the pyramids of Egypt to Greece and the Roman Empire.
Ancient World
Diocletian's Palace in Split: A Roman Emperor's Retirement Home
The palace housed the retired emperor and, from the 7th century, refugees from Salona, whose settlement grew into the city of Split.
Ancient World
Obelisks of Aksum: The Giant Stelae of Ancient Ethiopia
The tallest monolithic monuments of the ancient world; the Rome stela was returned to Ethiopia in 2005 and re-erected in 2008.
Ancient World
Armenia Adopts Christianity (301): Tiridates III and Gregory
Christianity became the official religion of the Armenian kingdom, and the Armenian Church was organised under Gregory and his descendants.
Ancient World
Great Persecution (303-311): Diocletian Against the Christians
The persecution failed to suppress Christianity; Galerius ended it with an edict of toleration in 311, and it was finally abandoned in the East in 313.
Ancient World
Nydam Boat: Iron Age Ship from a Danish Bog Offering (c. 320)
The oldest known large clinker-built rowing ship of northern Europe, preserved in a bog as part of a war-booty offering.
Ancient World
Disaster of Yongjia (311): The Sack of Luoyang by the Xiongnu
Han-Zhao forces sacked Luoyang and captured Emperor Huai, wrecking the Western Jin and driving many northern Chinese families south of the Yangtze.
Ancient World
Battle of the Milvian Bridge (312): Constantine's Victory
Constantine won decisively; Maxentius drowned in the Tiber and Constantine became sole ruler of the western Roman Empire.
Ancient World
Edict of Milan (313): Toleration for Christians in the Empire
Christians and all others gained legal freedom of worship, and property confiscated from the Church was ordered to be returned.
Ancient World
Arch of Constantine (315): Rome's Last Great Triumphal Arch
The Senate's arch celebrated Constantine's victory of 312 and survives as the largest and best-preserved Roman triumphal arch.
Ancient World
Leiden Plaque: A Maya Jade Record of a King's Accession in 320
A portable jade ornament that preserves one of the earliest Long Count dates from the Maya lowlands and an early image of Maya kingship.
Ancient World
Gupta Empire: The Golden Age of Classical India, AD 320-550
The Guptas built the largest Indian empire since the Mauryas and presided over a classical flowering of art, science and Sanskrit literature before declining in the 6th century.