Year 31 was a common year starting on Monday (link will display the full calendar) of the Julian calendar.

Events

By place

Roman Empire

• Lucius Aelius Sejanus is named co-Consul to the Emperor Tiberius. However, Tiberius becomes aware of Sejanus' treachery and has him arrested and executed.
• April 6 - (Good Friday) Crucifixion of Jesus (according to one dating scheme).
• Naevius Sutorius Macro becomes the leader of the Praetorian Guard after Sejanus is executed.
• Tiberius returns to Rome from Capri.

Births

• Musonius Rufus, Roman philosopher

Deaths

• October 18 - Lucius Aelius Sejanus, Roman politician (executed)
• Marcus Velleius Paterculus, Roman historian (possibly executed as an accomplice of Sejanus)
• Livilla, niece and daughter-in-law of the emperor Tiberius (starved to death for her role in a plot to overthrow Tiberius with her lover Sejanus)
• Saint Stephen, by stoning