Sejanus

Lucius Aelius Sejanus
Roman As depicting Tiberius, struck in 31. The reverse reads Augusta Bilbilis Ti(berius) Caesare L(ucius) Aelio Seiano, marking the consulship of Sejanus in that year.
Allegiance	Roman Empire
Years of service	14 AD – 31
Rank	Praetorian Prefect
Commands held	Praetorian Guard
Other work	Consul of the Roman Empire in 31

Sejanus (Lucius Aelius Seianus 20 BC – October 18, AD 31), was an ambitious soldier, friend and confidant of the Roman Emperor Tiberius. An equestrian by birth,^[1] Sejanus rose to power as Praetorian Prefect. He commanded the Roman imperial bodyguard, the Praetorian Guard, from AD 14 until his death in 31.

After the Praetorian Guard was established under Augustus, Sejanus introduced reforms which saw the unit go from a mere bodyguard to an influential branch of the government. It controlled public security, and influenced civil administration. Most important of all, it influenced the succession of emperors: all needed the goodwill and support of the Guard. These changes would have a lasting impact on the Empire.

During the 20s, Sejanus gradually accumulated power by influencing Tiberius and eliminating potential political opponents, including the emperor's son, Drusus. When Tiberius withdrew to Capri in 26, Sejanus was left in control of the entire state mechanism as de facto ruler 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.

1. ↑ Equestrians (~ knights) were the second class of Roman citizens, below the Patricians, but above the plebeians (the common people).