304
| Years: 300 301 302 303 - 304 - 305 306 307 308 | |
| Decades: 270s 280s 290s - 300s - 310s 320s 330s | |
| Centuries: 3rd century - 4th century - 5th century | |
Events
- Major Wu Hu (barbarian) uprising in China; the Hun Liu Yuan establish the Han kingdom, beginning the Sixteen Kingdoms era in China.
- Fincormachus becomes king of Scotland.
- Diocletian contracts a fatal illness.
Deaths
- Saint Agnes, Christian saint (martyred)
- Adrian of Nicomedia, Christian saint (or 303) (martyred)
- Pope Marcellinus on October 25 (martyred)
- Alban (possibly 309)
- Saint Lucie of Syracuse, Christian saint (martyred)
- Saint Afra, Christian saint (martyred)