The cause of the sudden and permanent decline of Roman oratory was the extinction of political life. Public speech could no longer be, as it had been for nearly two centuries, a great power in the commonwealth. Under the vigilant and judicious administration of Augustus there was not scope even for that kind of oratory which flourished under his successors, and became a very formidable weapon in the hands of the 'delatores,'--that, namely, which is employed in the prosecution and defence of men charged with grave offences against the State. Neither was there scope or inclination for philosophical or historical composition. Such freedom of enquiry as Cicero allowed himself in his treatises De Legibus and De Republica would scarcely have been tolerated under the monarchy; and the world was in no mood for any severe strain of thought or any questioning of the first principles of things. The new era desired ease, an escape from care and the perplexities of thought, as well as peace and material well-being. The spirit of the age was announced in the pastoral strain, which celebrated its commencement in the apotheosis of Julius Caesar, 'amat bonus otia Daphnis.' Nor would it have been possible for any one to have composed or at least to have published a candid history of the times; and it may have been the discovery of this impossibility that induced Asinius Pollio to leave his work unfinished. It would indeed have been a gain for all time had a Roman Thucydides recorded the 'movement in the State' from the Consulship of Metellus till the battle of Actium with the accuracy and impartiality, the graphic condensation, the sober dignity, the sensitive perception of the varying phases of passion and character in states and individuals, the philosophical discernment of great political principles destined to act in the same way 'so long as the nature of man remains the same,' and the deep tragic pathos which make, even at the present day, the record of 'the twenty-seven years' war of the Peloponnesians and Athenians' the most vividly interesting and permanently instructive historical work which the world possesses. But even had the genius of Rome been capable of producing a Thucydides, the circumstances of the time would have reduced him to silence. Tacitus regards the establishment of the Empire as equally fatal to the genius of the historian, as it was to the genius of the orator:--'Postquam bellatum apud Actium atque omnem potentiam ad unum conferri pacis interfuit, magna illa ingenia cessere. Simul veritas pluribus modis infracta, primum inscitia rei publicae ut alienae, mox libidine assentandi(85).'