The 3rd century
1,310 sourced entries across 100 documented years, grouped into 10 decades. A century here runs 1900–1999 rather than 1901–2000, so its decades sit inside it exactly; on the BC side the same rule puts 1–99 BC in the 1st century BC and 100 BC in the 2nd.
Decades
- The 200s — 10 years, 139 entries
- The 210s — 10 years, 146 entries
- The 220s — 10 years, 125 entries
- The 230s — 10 years, 125 entries
- The 240s — 10 years, 124 entries
- The 250s — 10 years, 169 entries
- The 260s — 10 years, 129 entries
- The 270s — 10 years, 145 entries
- The 280s — 10 years, 109 entries
- The 290s — 10 years, 99 entries
By subject
- Conflict & Security in the 3rd century — 241 entries
- Geopolitics & Diplomacy in the 3rd century — 90 entries
- Religion & Belief in the 3rd century — 89 entries
- Culture & Society in the 3rd century — 33 entries
- Exploration & Expansion in the 3rd century — 26 entries
- Crime & Justice in the 3rd century — 24 entries
- Economy & Finance in the 3rd century — 13 entries
- Technology & Infrastructure in the 3rd century — 11 entries
- Health & Medicine in the 3rd century — 10 entries
- Climate & Environment in the 3rd century — 8 entries
A few of the years
- 200September-November - Battle of Guandu: Chinese warlord Cao Cao defeats his rival Yuan Shao.
- 212The edict of Emperor Caracalla (Constitutio Antoniniana) extends Roman citizenship to all free inhabitants of the Roman Empire, with the exception of a limited group that may include Egyptians. The Jewish people are among those who receive citizenship. All free women in the Empire are given the same rights as Roman women.
- 224January 1 – Gaius Bellicius Torquatus and Appius Claudius Julianus II begin their one year terms as the new Roman consuls.
- 236January 10 – Pope Fabian succeeds Pope Anterus as the twentieth pope.
- 248Jungcheon becomes ruler of the Korean kingdom of Goguryeo (until 270).
- 260King Shapur I sends Valerian to Bishapur and uses the captured Roman army for engineering plans. They construct the Band-e Kaisar ("Bridge of Valerian").
- 272Aurelian supports the bishops of Italy in deposing the bishop of Antioch, Paul of Samosata, who had been a supporter of Zenobia. This is the first recorded instance of an imperial intervention in an ecclesiastical dispute.
- 284November 20 – The commander of Numerian's domestici (household troops), Diocles, is chosen to be the new emperor. In a military assembly outside Nicomedia (modern İzmit, Turkey), Diocles claims that the praetorian prefect (and rival for the throne) Arrius Aper murdered Numerian, and he personally stabs and kills the prefect on the spot. The new emperor changes his name to the Latinised 'Diocletian'. Building on existing trends, Diocletian presents his rule as that of a god-like dominus or autocrat.