31Centuries: 1st century BC - 1st century - 2nd century
- Aelius Sejanus named co-Consul to the Emperor Tiberius
- Naevius Sutorius Macro becomes the leader of the Praetorian Guard after Sejanus is executed.
- Aelius Sejanus, Roman politician (executed)
- Marcus Velleius Paterculus, Roman historian (possibly executed as an accomplice of Sejanus)
For the number 31, see thirty-one.