He aimed not only to give moral edification by parading virtue and vice, but to give practical instruction. This justified his attention
to intrigue and treason trials. Under the Republic, he explains, when power was at one time with the plebs, at another with the
Senate, one had to discover how to manage the masses and equally how to influence the nobles who dominated the Senate. By the
same token under an autocracy it was helpful to understand how an Emperor's mind worked. It was for success in this respect that
Tacitus was so admired by men like Machiavelli and Guicciardini in the Renaissance. Although he gave their due to those who were
destroyed by Emperors, he reserved his greatest admiration for those, like himself and his father-in-law Agricola, who survived. 'Let
all those whose habit is to admire acts of civil disobedience, realize that great men can exist under bad emperors, and that
compliance and an unassuming demeanour, if backed by energy and hard work, can attain a pitch of glory, which the majority reach
through an ostentatious and untimely death.' He had no illusions about the leading victims of the Julio-Claudians, pointing out how
they tried to maintain status by self-display and extravagant spending, and contrasting them with the modest and parsimonious new
men brought into the senate.
As a historian of the Empire he is most interesting for his ability to put the case for the opposition, not only denouncing the
corruption of Roman rule (part of a Roman orator's stock-in-trade in so far as he had to appear for Rome's subjects in extortion
cases), but also highlighting courageous independence and resistance to the blandishments of Roman civilization. 'If you wish to rule
everyone, does it follow that everyone should accept slavery?', asks the captured British leader Caratacus. A feature of that slavery
was 'the amenities that make vice agreeable-porticoes, baths, and sumptuous banquets'. On the other hand he could contrast the
peace and justice that Roman rule brought with the insecurity of tribal rivalries. Most revealing, however, is the comment attributed
to a Roman commander rejecting a plea from a German tribe to be allowed to settle in Roman territory. 'Men must obey their betters:
the gods they invoked had empowered the Romans to decide what to give and what to take away, and to tolerate no judges but
themselves.'
Tacitus lamented the lack of military material available to him. Yet, though he can give an exciting and not inaccurate account of a
campaign (like Livy, he is especially effective in portraying the feelings of the men involved), his style leads to an irritating
vagueness about detail. This style, however, was admirably suited to the portrayal of imperial politics. Two chief features were
irony, used to contrast the appearances of public life with the underlying realities of power, and a deliberate cultivation of ambiguity.
Tacitus delights in the deflating postscript. He also has an elaborate technique of providing alternative explanations-some his own,
some ascribed to others-which do not clarify but increase the uncertainty over the motivation of those he describes. His classic
achievement was his portrayal of Tiberius. His sources reported an Emperor who, in spite of great talents and a concern for the well-
being of the Empire, ended his life with an intermittent grasp over his administration and abominated by his people. Tacitus seized
on Tiberius' well-known hypocrisy as the answer to the enigma, and saw his life as the gradual peeling of skins of plausibility from a
bitter and malevolent inner self. Tiberius was presented as a man of acute intelligence warped by his early life and love of
domination. Guicciardini wrote, 'Cornelius Tacitus teaches very well every man who lives under a tyrant the way to live and manage
his affairs prudently, just as he equally teaches tyrants the ways to found their tyranny.'