321
Year 321 (CCCXXI) was a common year starting on Sunday (link will display the full calendar) of the Julian calendar. In the Roman Empire, it was known as the Year of the Consulship of Crispus and Constantinus (or, less frequently, year 1074 Ab urbe condita). The denomination 321 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

Events
By topic
Roman Empire
Emperor Constantine I expels the Goths from the Danube frontier and repairs Trajan's Bridge. He leads an expedition into the old province Dacia (modern Romania) and makes peace with the barbarians.
March 7 - Constantine I signs legislation directing urban residents to refrain from work, and businesses to be closed, on the "venerable day of the Sun". An exception is made for agriculture.

Asia
Tuoba Heru launches a coup d'état against his cousin Tuoba Yulü and becomes the new Prince of Dai.

By topic
Art and Science
Calcidius translates Plato into Latin.

Food and Drink
Constantine I assigns convicts to grind Rome's flour, in a move to hold back the rising price of food in an empire whose population has shrunk as a result of plague.

Religion
The Christian Church is allowed to hold property.
A synod held in Alexandria condemns Arianism.
History of the Jews in Germany: Jews in modern-day Germany are documented for the first time, in Colonia Agrippinensium (modern-day Cologne).

Births
Cheng of Jin (or Shigen), Chinese emperor (d. 342)
Du Lingyang (or Chenggong), Chinese empress (d. 341)
Valentinian I ("the Great"), Roman emperor (d. 375)

Deaths
Tuoba Yulü, Chinese prince of the Tuoba Dai
Zu Ti (or Shizhi), Chinese general and adviser (b. 266)


== References ==