INTRODUCTION

The imposition of monarchy changed Roman political culture but to a remarkable extent preserved the existing political structure. The first emperor, Augustus (31 bc–ad 14), boasted that he had restored the Republic. This was partly propaganda designed to legitimate his reign, and to obscure his innovations. There was also some truth in it. But why did a monarch restore the Republican constitution? One partial answer is that the oligarchic system of power-sharing had significant advantages for a monarch who wanted the support of aristocrats, but who also wanted to fragment the power of each so that it did not constitute a danger for himself. The maxim, divide and rule, was applied to senators as well as to barbarians. The persistence of the Republican constitutional forms was in the emperors' interest.

But the emperors' self-interest is not a sufficient explanation. Emperors were also constrained by tradition and by the lack of alternatives. Emperors had to delegate power. In choosing generals, judges and provincial governors, they had little choice but to rely in the first instance on aristocrats, and to reward the new men to whom they gave elite positions with the traditional marks of aristocratic status. They also used knights and ex-slaves of the imperial household in a wide range of supervisory positions, but more as checks on senatorial governors than as their replacements. After all, the emperors were conservative not revolutionaries; too much change would have undermined their own legitimacy.