|Centuries:||2nd century – 3rd century – 4th century|
|Decades:||220s 230s 240s – 250s – 260s 270s 280s|
|Years:||247 248 249 – 250 – 251 252 253|
- Diophantus writes Arithmetica the first systematic treatise on algebra.
- A group of Franks penetrate as far as Tarragona in Spain (approximate date).
- Goths invade Moesia.
- The Alamanni drive the Romans from the modern area of Donau-Ries.
- Decius begins a period of persecution of the Christians in the Roman Empire.
- Teotihuacán is rebuilt as a four-quartered cosmogram by Zapotec architects brought from Monte Albán in Oaxaca.
- Kofun Period begins in Japan.
- for more information, see Category:250 births.