Epideictic oratory had a lasting influence on both the rhetorical and the oratorical traditions. The preliminary exercises (progymnasmata) which formed the cornerstone of rhetorical training in the Roman period included both praise ( enkomion) and invective (psogos), refutation (anaskeue) and confirmation (kataskeue) of a range of issues. Though only encomium and psogos would have been recognized as epideictic, all are ultimately and unmistakeably descended from the epideictic oratory of the fifth and fourth centuries. The same is true of the Roman and Greek declamations; thus Libanius’ defence speech for Socrates (fourth century AD) visibly belongs to the same tradition as Polycrates’ accusation centuries before, as for instance do the various speeches for imaginary political occasions composed by Libanius’ contemporary Himerius.
The zenith of epideictic oratory under the Roman empire was the second century AD, the period of the classicising movement known as the Second Sophistic. In this period we find a renewed confidence in Greek writers, alongside a passion for both the oratory and the dialect of the Athenian orators of the classical period. Part of that renaissance is the emergence of public orators who attracted large audiences to speeches on social, ethical and political themes. We have only a single (spurious) speech purporting to be the work of Herodes Atticus and except among cultural historians his name survives more for the Odeum on the Acropolis at Athens which bears his name. But he is spoken of with great enthusiasm by Philostratus in his Lives of the Sophists and the Suda speaks of the lofty sentiments expressed in his work. Two declamations attributed to the celebrated rhetorician Polemon survive, in which two fathers compete under a (fictitious) law to deliver a funeral oration each for his own son. The balanced and contrasting speeches are in the same tradition ultimately as the Tetralogies of Antiphon. Better represented are two of their contemporaries, Dio of Prusa and Aelius Aristeides. Aelius’ work has a very wide range. It includes prose hymns, which in their occupation of the position traditionally assigned to verse reminds us of the earliest period of Greek sophistic activity, as do several compositions of Himerius in the fourth century, such as his prose celebration of the wedding of Severus (Speech 9), an area occupied by lyric poetry in the archaic and classical period. It includes fictive speeches linked to real occasions, such as the speech (supposedly) addressing the Athenian Assembly in response to Nicias’ request for reinforcements in Sicily. It also includes speeches engaging with longstanding debates, such as Plato’s attack on rhetoric. Dio’s work is still more variegated. Often what we have would be better described as sermons, moralizing essays of a generalizing nature, sometimes appended to allegedly autobiographical experiences. As in the classical period, this remains a profoundly serious activity.37