The two problems to be discussed here are :—
(1) Under what law or laws were charges brought in cases of treason during the first years of the Principate?
(2) What were the penalties prescribed by that law or those laws?
The answer to the first question raises no serious difficulties. It is true that apart from any consideration of perduellio no fewer than four laws de maiestate (to be discussed more fully later) were passed in the seventy years before the reign of Augustus. But it is clear that for all practical purposes these laws were comprehended and superseded by the Lex Julia of Augustus. Tacitus always speaks of a single law, e.g.
Ann. 1, 72, 3: ‘nam legem maiestatis reduxerat,’ and
Ann. 2, 50, i: ‘adolescebat interea lex maiestatis’
and the jurists always refer to a Lex Julia which must have been that passed by Augustus and not that of Caesar.
The answer to the second question also was until recently regarded as practically certain. It was held by all authorities, both Continental and English, that the only legal penalty was ‘interdictio aquae et ignis’, though with the establishment of the Principate there began a process of arbitrarily worsening the conditions of exile and even substituting the death penalty. But during the present century another view has been put forward—a view developed in most detail by R. S. Rogers in his Criminal Trials and Criminal Legislation under Tiberius (1935). In this book Rogers asserts positively and often that the Lex Julia embraced two different kinds of treason—high treason, which he calls by the old name of Perduellio, and Maiestas, which often amounted to no more than slander of the Princeps or his family—and that two different penalties were prescribed, viz. death (with confiscation of property and damnatio memoriae) for Perduellio, exile for Maiestas.