Tacitus' Annals set out to cover the history of the Roman Empire from the death of Augustus and the accession of Tiberius to the later part of Nero's reign. Sadly, large parts of his text are lost including his description of the whole of Caligula's reign and the early part of that of Claudius, but what remains gives us our most detailed picture of Imperial rule. As Tacitus' final and most mature work, the Annals exhibit his strong grasp of power politics and his lucid insight into imperial psychology. The deterioration of senatorial freedom and of the moral character of the aristocracy under Tiberius, whose reign starts well but ultimately descends into quasi-tyranny, is well-portrayed, and his detailed portrait of Tiberius is memorable. Tacitus throughout seeks to maintain an objective balance, basing his narrative on solid evidence, and documentary sources, yet also takes the opportunity to express his own views and feelings regarding the abuse of power, the corruption displayed by individuals, and the character faults which undermined Imperial rule, especially in his handling of Nero's reign.