Later in 29, owing to the intrigues of Sejanus, and at the insistence of Tiberius, Nero and Agrippina were accused of treason. Nero was declared a public enemy by the Senate and taken away in chains in a closed litter. Nero was incarcerated on the island of Pontia (Ponza). The following year he was executed or driven to suicide. Cassius Dio records that Julia was now engaged to Sejanus, but this claim appears to be contradicted by Tacitus, whose authority is to be preferred. Sejanus was condemned and executed on Tiberius’ orders on 18 October 31. His lover, Julia’s mother Livilla, died around the same time (probably starved by her own mother: Julia’s grandmother Antonia, or committed suicide).