 In 31 AD, a plot by her daughter Livilla and Tiberius’ notorious Praetorian prefect, Sejanus, was exposed by Apicata, the estranged ex-wife of Sejanus, to murder the Emperor Tiberius and Caligula and to seize the throne for themselves.Livilla allegedly poisoned her husband, Tiberius' son, Drusus Julius Caesar (nicknamed "Castor"), in 23 AD to remove him as a rival.Sejanus was executed before Livilla was implicated in the crime.