Treason was the worst of crimes. Perduellio, or ‘acting like an enemy (perduellis)’ menaced the safety of the whole community, and its punishment was correspondingly harsh: the traitor would be publicly flogged and crucified. The Twelve Tables ordained punishment for ‘the man who incites an enemy or who hands over a citizen to an enemy’ (D. 48.4.3). Tacitus' brief sketch of the treason law at the start of Tiberius' reign merged perduellio with ‘damage to’ maiestas (for their use in accusations, see Rogers 1933) and reminded his readers that the law encompassed the betrayal of an army, seditious incitement of the people and any act by which ‘the maiestas of the Roman people was diminished’ (Ann. 1.72). Problems of definition and the strong feelings aroused by alleged abuse of the charge for private gain can obscure the importance and seriousness of the offence.

FROM SATURNINUS TO CAESAR

The merging of the ancient crime of treason and the offence of maiestas was probably due to a law of L. Appuleius Saturninus in 103 or 100 bc (despite attestation of earlier use of the term). The original context of Saturninus' reform was political and highly partisan. Saturninus' reforms in general extended the power of the populus over its executive, the magistrates and Senate, and included active interference in the administration of the provinces and provincial commands (as in the Delphic Piracy Law) and the imposition of oaths on senators that they would obey the laws (Lintott 1994: 95–101).