INTRODUCING THE PRINCIPATE 9traditionally senatorial territory, and others that were novel, notably, the
fashioning of the image of the emperor and the propagation of the ideology
of the new regime.^17 Senators co- opted onto this body would have rubbed
shoulders with members of the equestrian order, including the éminences
grises Maecenas and Sallustius Crispus, top equestrian offi cials (for example,
the praetorian prefect), and members of the royal house including potential
heirs.^18 Senators, again as individuals, provided vital service as commanders
and administrators. In fact throughout the period of the Principate senators
all but monopolised the command of the legions and governed most of the
provinces. The downside was that high- placed senators might fall foul of
suspicious or jealous emperors. On the other hand when a dynasty imploded
or dried up through lack of heirs, it was invariably a senator who succeeded,
whether through military intervention or adoption. There was only one
exception, Macrinus, who removed and replaced Caracalla (217).
The contrast is stark between the greatly diminished role of the senate as
an institution and the extensive employment of senators in the government
of Rome and the empire. This is the case even though the senate did not lack
all corporate functions and actually acquired new ones. Under the Republic
it was not a court of law, but emperors allowed it judicial responsibilities in
specifi c areas, in particular in criminal cases involving senators.^19 Similarly,
the Republican senate was not a legislature, but more than 200 senatorial
resolutions, mainly concerning status, inheritance and the maintenance of
order, are known from the fi rst three centuries of the empire.^20 Further, in
both the judicial and legislative spheres, imperial activity undermined
existing institutions. Thus, while the civil courts and the criminal jury- courts
( quaestiones ) continued to operate – the latter were reorganized under
Augustus in two signifi cant statutes and a new court was added to deal with
adultery – they were increasingly overshadowed by imperial jurisdiction,
both fi rst- order and appellate, and that of other tribunals to which the
emperor delegated cases.^21 This process was already beginning under
Augustus (Suet. Aug. 33; Val.Max. 7.7.3–4; Dio 55.7.2). The new courts
employed a simplifi ed procedure, cognitio , based on interrogation by the
judge.^22 Again, while Augustus was careful to promote legislation through
the assemblies by means of his tribunician power (see below), he also issued
decrees and edicts and wrote letters, in a word, ‘constitutions’, which were
treated as binding. According to the jurist Gaius, who wrote in the mid-
second century, ‘it has never been doubted’ that a constitution of the emperor
had the force of law, whereas the legal validity of senatorial resolutions ‘has
been questioned’ ( Inst. 1.2). His explanation may be less than convincing –
‘because the emperor has received his imperium through a lex’ – but the fact
is beyond dispute. Certainly by the time of Gaius imperial constitutions had
become the main source of law at the expense of enactments issuing from
popular assemblies, comitia. As we shall see, there was one area in which
comitial legislation survived and was of singular importance: the conferral
of powers on the emperor.