10 THE ROMAN EMPIRE
One function of the senate, a highly signifi cant one, remains to be
discussed. It became customary for the senate to confer legitimacy on a new
emperor by formally approving his accession, and to pass judgement on a
dead emperor by voting to deify him (Augustus), or damn his memory
(Domitian) – or do nothing (Tiberius). This tradition had its origin in the
manoeuvrings of Augustus in 28–27 BC when he was seeking to make the
transition from military dynast to Princeps.
The challenge facing Augustus after his triumph on the battlefi eld was to
arrive at a defi nition of his own powers in relation to the established organs
of Roman government that would not offend senatorial sensitivity, while
safeguarding his dominant position in the state. The formula he had arrived
at by 23 BC involved the grant by the senate and Roman people of proconsular
imperium (for ten years or fi ve years, not for life), and tribunician power
(‘annual and perpetual’). Imperium proconsulare was power exercised
abroad by a pro- or ex- magistrate of consular rank. In the case of Augustus
this was imperium with a difference. He exercised direct control over a huge
province, which included Gaul, Spain and Syria, where the Roman military
presence was most required and the bulk of the army was stationed, and had
authority greater ( maius ) than that of other provincial governors, including
those chosen by the senate. Moreover, his proconsular imperium could be
held in Rome itself. As to tribunicia potestas: the utility of the tribunician
power to Augustus is harder to pin down. A tribune had formidable powers,
notably the negative power of vetoing senatorial resolutions and preventing
magisterial actions, and the positive power of carrying legislation through
the plebeian assembly.^23 However, Tacitus picks out as attractive to Augustus
the symbolic role of the tribune as protector of the common people
against the aristocracy ( Ann. 1.2), and it was to enable the tribune to exercise
this role with impunity that he was awarded sacrosanctity. Tacitus later
describes the tribunicia potestas as a title ( Ann. 3.56: vocabulum ), and it is
to be noted that Augustus and all other emperors under the Principate dated
their reigns by the tenure of tribunician power. Thus Augustus may well
have valued it as much for its associations as for its prerogatives. His career
up to this point had been marked by subtle choice and clever exploitation of
names and titles. ‘Caesar’ secured the loyalty of the soldiers for ‘the boy’
Octavian, aged 19, while ‘princeps’ advertised his interest, as Augustus, in
ridding himself of the image of party leader and dynast. The name recalls the
princeps civitatis of Cicero’s De Re Publica , who dominates the state by
virtue of moral authority rather than physical force or even constitutional
offi ce. ‘Augustus’, on the other hand, was a ‘fi rst’, and implied that its bearer
was especially favoured by the gods of Rome.^24 In the Res Gestae Augustus
mentions various titles, and lists his many religious offi ces, but is silent on
the subject of the imperium that was the basis of his power.
Augustus wrote: ‘I would not accept any offi ce against the custom of our
ancestors’ ( Res Gestae 6.1). His circumspection with regard to constitutional
forms is borne out by his refusal in the years after 23 BC to accept a