Divus Marcus et Commodus Scapulae Tertullo rescripserunt in haec verba: ‘si tibi liquido compertum est Aelium Priscum in eo furore esse, ut continua mentis alienatione omni intellectu careat, nec subest ulla suspicio matrem ab eo simulatione dementiae occisam: potes de modo poenae eius dissimulare, cum satis furore ipso puniatur. et tamen diligentius custodiendus erit ac, si putabis, etiam vinculo coërcendus, quoniam tam ad poenam quam ad tutelam eius et securitatem proximorum pertinebit. si vero, ut plerumque adsolet, intervallis quibusdam sensu saniore, non forte eo momento scelus admiserit nec morbo eius danda est venia, diligenter explorabis et si quid tale compereris, consules nos, ut aestimemus, an per immanitatem facinoris, si, cum posset videri sentire, commiserit, supplicio adficiendus sit. cum autem ex litteris tuis cognoverimus tali eum loco atque ordine esse, ut a suis vel etiam in propria villa custodiatur: recte facturus nobis videris, si eos, a quibus illo tempore observatus esset, vocaveris et causam tantae neglegentiae excusseris et in unumquemque eorum, prout tibi levari vel onerari culpa eius videbitur, constitueris. nam custodes furiosis non ad hoc solum adhibentur, ne quid perniciosius ipsi in se moliantur, sed ne aliis quoque exitio sint: quod si committatur, non immerito culpae eorum adscribendum est, qui neglegentiores in officio suo fuerint.’
(Macer, Digesta Iustiniani 1.18.14)
The deified Marcus and Commodus issued a rescript to Scapula Tertullus in the following terms: “If you have clearly ascertained that Aelius Priscus is in such a state of insanity that he lacks all understanding through the continuous alienation of his mental faculties, and if there remains no suspicion that his mother was murdered by him under pretence of madness; then you can abandon consideration of the measure of his punishment, since he is being punished enough by his very madness. And yet it will be necessary for him to be all too closely guarded, and, if you think it advisable, even bound in chains, this being a matter of not so much punishing as protecting him and of the safety of his neighbors. If, however, as very often happens, he has intermittent periods of relative sanity, you shall diligently explore the question whether in one such moment he committed the crime, and whether no indulgence is due to his illness. If you ascertain any such thing, you shall consult us, that we may consider whether the enormity of his crime (in the event of his having committed it when he could be held to have been fully aware) merits the infliction of extreme punishment. But since we have learned from your letter that his position and rank are such that he is in the custody of his own people or even in his own house, it seems to us that you will act rightly if you summon those by whom at the material time he was being looked after, and if you make inquiry into the cause of so neglectful an act, and if you make a decision against each one of them according as you find his culpability lesser or greater. For those who have custody of the insane are not responsible only for seeing that they do not do themselves too much harm but also for seeing that they do not bring destruction on others. But if that should happen, it may deservedly be imputed to the fault of those who were too neglectful in performing their duties.” (tr. Alan Watson)
Crambe Repetita 