250

250 (CCL) was .

 Events 
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.

 Births 

 Helena of Constantinople
 Licinius