This paper argues for the revolutionary content of the lex Iulia de senatu habendo within the context of Augustus’ greater legal program. The law was an effort to codify the rules of senatorial procedural, which had been controlled by unwritten and unofficial mos during the Republic. Although this law is discussed in scholarship on the Roman senate (Talbert ), it carries a question-mark rider in the traditional list of Roman leges (G. Rotondi, LegesPublicae Populi Romani [Milan 1912]) and is often excluded from major discussions of the Augustan laws, which are focused largely on the ‘moral’ reforms of the princeps (as in K. Galinsky, Augustan Culture [Princeton1986] 128-138), and from more general considerations of the Augustan principate (it is relegated to a footnote in D. Kienast, Augustus: Princeps und Monarch [Darmstadt 1982]) and its ideology (such as J. Beranger, Recherches sur l'aspect idéologique duprincipat [Basel 1953]).
In two parts, this paper will correct this error and attempt to reviveinterest in the law: First, I will briefly outline the evidence for the existence, date, and content of the law. The sources for the law are literary: the title comes from Pliny (Ep. 5.13.5, 8.14.19-20) and Gellius (4.10.1); Dio (55.3) discusses the provisions of the law; Suetonius (Aug. 35) seems to refer to the law in his discussion of Augustan reforms of the Senate (though he does not name it); and Seneca (De brev. vitae 20) makes a passing reference to the lex. The use of the singular ‘lex’ in the letters is a precise legal term referring almost always to a Republican or Augustan statute and Pliny Ep. 5.13.5 confirms the existence of the law and, most likely, its title. Our only source for the dating of this law, Dio (55.3) places the statute in his record of the year 9 BC. While the exact provisions of Augustus’ statute are not fully recoverable, it likely contained specific stipulations on nearly all elements of Senate operation, such as quorums and the proper sequence of meetings.
In the second part of the paper, I will argue that by legislating on senatorial procedure, Augustus irrevocably altered the Republican constitution, which had kept separate the mos-controlled Senate from the lex-controlled magistracies. There is no record of the codification of senatorial procedure during the Republic and the Republican Senate seems to have been governed entirely by reliance on mos and by the handing down of rules of order from generation to generation (as described in Pliny Ep. 8.14). The Augustan lex de senatuhabendo wrote down what had always been unwritten. An analysis of the discussion in Pliny Ep. 8.14.19 illustrates the reality that senatorial procedure under the Empire relied on a law and proper interpretation of its stipulations. Pliny quotes directly from the statute and breaks down the particularson its regulations concerning the procedure for voting in criminal sentencing involving death and banishment. Pliny’s analysis of the written text illustrates the reality that senatorial procedure under the Empire relied on a law and proper interpretation of its stipulations. Changes in senatorial procedure between Republic and early Empire appear to have been gradual, often informal, and usually impossible to date (Talbert  221-222). There is no evidence that Augustus’ reforms significantly altered the procedure of Cicero’s Senate and senatorial procedure would not have been fundamentally different inPliny’s day. What was revolutionary about the Augustan statute was not any changes it made to senatorial procedure, but the fact that the princeps was using a lex to govern the Senate. Augustus’ exertion of his own magisterial power as lawmaker over the Senate was a subordination of the Senate’s authority to that of the princeps.