The Augustan constitution—if we may use this word, for which there is no ancient equivalent—is as important a subject as the large number of modern writings devoted to it would suggest, and to judge by their contradictory character, it is a difficult one. Anyone who attempts, as I am attempting to-day, yet another general statement, and that within the compass of a single paper, must hedge himself around with protestations and admissions of what he is going to leave out. I must also at once forestall the criticism, frequently launched at students of this subject, that I am the dupe of ancient propaganda, inscriptions including the Res Gestae, and the coins. I fully appreciate that their insinuating suggestions are constantly misleading; and yet they, as the principal contemporary sources, are what I chiefly propose to quote to you to-day. I must also concede that these sources show a meticulous correctness of terminology, concerning matters such as the legal nuances distinguishing various powers, which must have been lost on considerable sections of the general Roman public. But these sections of the public should not be the concern of a student of the Augustan constitution. His concern is rather with the governing class, the fabricators of this insidious publicity. They, at least, were very far from averse to constitutional niceties; and incidentally, against those who stress the ignorance of the public, these hard-headed men would never have taken so much trouble if nobody was going to be impressed by it.
But I am not plunging into the full intricacy of their efforts to-day; for the compass of one paper requires simplification, and one way in which I shall simplify is by ignoring the many nuances between different categories of power, and considering them as subdivided into two main categories only—on the one side that sort of power which was part of the legal and formal machinery of the State, a potestas, including some powers carrying imperium and some lacking it, and on the other side all those media of authority which were not based on any potestas.