On this day in A.D. 31, Sejanus, the stand-in for Tiberius, Rome's second emperor, was executed. After he was killed, his disgraced body was tossed onto the Scalae Gemoniae and torn to pieces. Then came riots in which the mob hunted for people who were associated with Sejanus. The Senate issued a damnatio memoriae, a futile, but symbolic attempt to erase the memory of such a despised individual.
When Tiberius came to the throne, he appointed the equestrian Sejanus praetorian prefect. Sejanus began to manipulate the praetorian guard into a personal guard for the emperor for efficiency and power. When Tiberius' son Drusus died in 23, Sejanus tried to marry his widow Livilla. Even without the marriage, he continued to amass power, and when Tiberius retired to Capri in 27, Sejanus was left as regent. Sejanus became co-consul with Tiberius in 31.
Read more about Sejanus.