Lucius Seius Strabo (46 BC – after 16 AD) was a prefect of the Roman imperial bodyguard, known as the Praetorian Guard, during the rule of the emperors Augustus and Tiberius.
The length of Strabo's tenure as Praetorian prefect is unknown, but he held the position together with various colleagues until 15, after which he was appointed to the governorship of Egypt.
With this career Strabo distinguished himself by attaining the two highest offices open to men of the equestrian class in the Roman Empire.
His son was Lucius Aelius Sejanus, who succeeded his father as Praetorian prefect in 15, and gained great influence under Emperor Tiberius before dramatically falling from power in 31.
This made them relatively harmless and consequently, suitable for important offices of state such as Praetorian prefect or governor of Egypt; the former post which was in charge of the Emperor's personal bodyguard, the latter which controlled the grain supply of Rome.
[5] During Republican times, generals or statesmen had relied on private corps of soldiers before, but the Guard as established by Augustus differed from these early cohorts, not only in structure and number but also in function.
[15] Together they commanded the Praetorian Guard from 14 until 15 or 16, after which Strabo was promoted to the highest office a Roman knight could attain, governor of Egypt.
[18] Although Strabo distinguished himself by achieving the highest offices a Roman knight could attain under Augustus and Tiberius, his place in history has been largely overshadowed by the infamy of his son Sejanus.
During a prefecture which lasted nearly 17 years, Sejanus introduced reforms to the Praetorians which helped shape the Guard into an integral and powerful branch of the Principate.