Approximate birth of Constans to Constantine I and Fausta.
December 25
Constans elevated to Caesar at Constantinople by Constantine I
September 9
Death of Constantine the Great. Constans, Constantine II, and Constantius II become emperors and divide the empire.
Constans campaigns against the Sarmatians.
Constantine II attempts to dictate legislation to Africa, which is part of the territory of his brother, Constans.
Constantine II leads an army into Italy against his brother Constans, only to be ambushed and killed. Constans takes over the territory of Constantine II.
Constans leads a campaign against the Franks, though is initially defeated.
Constans issues an edict banning superstition and pagan sacrifices.
Constans defeats the Franks and signs a favorable treaty.
Constans and Constantius II hold the Council of Serdica to settle a dispute over the bishop Athanasius of Alexandria. There is no agreement.
February
Constans visits Britain.
Constantius II and Constans nearly start a civil war, until Constantius allows Athanasius to return to his position in Alexandria.
January
Magnentius, commander of a corps in the Roman army, overthrows and kills Constans.