321

321 (CCCXXI) was a common year beginning on a Sunday of the Julian calendar, in force on that date.

In the Roman Empire, the year was named as the year of the consulate of Crispus and Constantine, or less commonly, as 1074 Ab Urbe condita, acquiring its name as 321 at the beginning of the Middle Ages, when the anno Domini was established.

Events

• 7th March: the Roman emperor Constantine declares on Sunday (“venerable day of the Sun”) as the seventh day of the week, instead of the Sabbath.
• Calcidio translates the first part of Timeo (by Plato) to Latin.
• The Catholic Church is allowed to own property.
• In Antioch (Turkey), a synod of bishops condemns arianism.

Births

• Valentinian I, Roman emperor.
• Wáng Xīzhī (.щ), Chinese pen.