Sejanus

Lucius Aelius Sejanus
Roman As depicting Tiberius, struck in 31, Augusta Bilbilis. The reverse reads Augusta Bilbilis Ti(berius) Caesar L(ucio) Aelio Seiano, marking the consulship of Sejanus in that year.
Born	June 3, 20 BC Volsinii, Etruria
Died	October 18, 31 AD (aged 50) Rome
Allegiance	Roman Empire
Years of service	14 AD – AD 31
Rank	Praetorian prefect
Commands held	Praetorian Guard
Other work	Consul of the Roman Empire in 31

Lucius Aelius Sejanus (June 3, 20 BC – October 18, AD 31), commonly known as Sejanus (English pronunciation: /sᵻˈdʒeɪnəs/), was an ambitious soldier, friend and confidant of the Roman Emperor Tiberius. An equestrian by birth, Sejanus rose to power as prefect of the Roman imperial bodyguard, known as the Praetorian Guard, of which he was commander from AD 14 until his death in AD 31.

While the Praetorian Guard was formally established under Emperor Augustus, Sejanus introduced a number of reforms which saw the unit evolve beyond a mere bodyguard, into a powerful and influential branch of the government involved in public security, civil administration and ultimately political intercession; changes which would have a lasting impact on the course of the Principate.

During the 20s, Sejanus gradually accumulated power by consolidating his influence over Tiberius and eliminating potential political opponents, including the emperor's son, Drusus Julius Caesar. When Tiberius withdrew to Capri in 26, Sejanus was left in control of the administration of the empire. For a time the most influential and feared citizen of Rome, Sejanus suddenly fell from power in 31, the year his career culminated with the consulship. Amidst suspicions of conspiracy against Tiberius, Sejanus was arrested and executed, along with his followers.

Sejanus was born in 20 BC at Volsinii, Etruria, into the family of Lucius Seius Strabo. The Seii were Romans of the equestrian class (or knights), the lower of the two upper social classes of the Roman Republic and the early Roman Empire. Sejanus' grandfather maintained relations with senatorial families through his marriage with Terentia, a sister of the wife of Gaius Maecenas, who was one of Emperor Augustus' most powerful political allies.