306 CE
A year that set the stage for one of history's most consequential reigns, as Constantine was proclaimed emperor by his troops at York following the death of his father Constantius Chlorus.
Geopolitics & Governance
- Emperor Constantius Chlorus died on July 25 at Eboracum (modern York) in Britain, and his son Constantine was immediately proclaimed Augustus by the legions stationed there.
- Constantine's proclamation violated the rules of the Tetrarchy established by Diocletian, under which successors were to be chosen by merit rather than hereditary descent, setting the stage for years of civil war.
- Maxentius, son of the retired emperor Maximian, seized power in Rome on October 28, further destabilizing the Tetrarchic system and setting up a future confrontation with Constantine.
- The Roman Empire was now divided among multiple claimants, with Constantine controlling Britain and Gaul, Maxentius holding Italy and Africa, and other tetrarchs controlling the eastern provinces.
Culture & Society
- The world population was approximately 238 million.
Climate & Environment
- Atmospheric carbon dioxide concentration was approximately 278 parts per million, as later confirmed by ice core analysis.