When Tacitus summarised Tiberius’ life at the end of his account, he concentrated on the deterioration of Tiberius’ personality, which he perceived as a gradual process in which the ‘true character’ of the princeps was revealed by stages. These were determined by Tiberius’ relationship with various members of his family and entourage, and only after the death of Sejanus in ad 31 did his character become fully apparent.