Abstract
A session of the Roman Senate held in 20 AD, under Tiberius, provides an opportunity to study the relationship between law and morality. Tacitus(Ann., 3, 25), who recounts the event, evokes the consequences of the Papia Poppaea law, passed in 9 AD at Augustus' instigation, to reinforce the Iulia de maritandis ordinibus law (18 BC), which encouraged marriages. Measures concerning the transmission of patrimony, in particular property that had lapsed in the absence of successors, reverted to the public treasury : in addition to encouraging procreation, the Papia Poppaea law created new tax resources. Any citizen could claim from the public treasury the property that had lapsed : Tacitus evokes the harmful consequences of this denunciation and, above all, the endangerment of patrimony. A medical metaphor depicts the effects of the law : the remedies are worse than the ills. For Tacitus, laws, initially powerless to curb bad morals, are then contaminated by them. The failure of the remedy, the impotence of the law (a phenomenon already deplored by Plautus, Trin., 1039-1040), manifests itself in the multiplication of laws, just as medicines multiply according to the spread of diseases (Sen., Ep., 95, 15). To explain this legislative hypertrophy, Tacitus goes back to the principia iuris, like Cicero before him and Gaius after him : the past becomes a tool for understanding. Tacitus evokes a regressive dynamic, from golden age to chaos(Ann., 3, 26-28).
Then come kings and laws. As with medicine, the laws are initially crude, then increasingly refined. The Law of the Twelve Tables, in the5th century BC, is defined as finis aequi iuris, the rule of equitable law, but also the ultimate term before decadence. It was above all the century from the Gracchi to Augustus that turned the law into an instrument of political struggle between factions and imperatores, with the failures of Sylla, " dictator legibus scribundis et rei publicae constituendae ", then Pompey, " corrector morum " during his sole consulship in 52 BC. J.-C. Tacitus - concluding his digression - returns to the present with Augustus : in 28 BC. After the negative, oppressive legislation of the Civil War, and with the repeal of triumvirate norms, positive, moralizing legislation was introduced. This new beginning is confirmed by an aureus from the same year, probably the only Roman coin in which the prince appears in a legal context : the legend " Leges et iura p(opuli) R(omani) restituit " indicates that Augustus restored the leges and iura of the Roman people. But the balance between the prince's power and well-balanced standards was short-lived. From now on, society suffers because of laws with perverse effects. This is precisely what happens with the lex Papia Poppaea. Not only the matrimonial laws, but also the sumptuary laws failed, not least because, according to Tacitus, although Augustus presented himself as the physician of a sick society, his behavior failed to arouse the desire to imitate the prince, a desire that would be stronger than the fear of the laws.
