Beyond determining the genre, length, and focus of the various strands of the literary tradition, the historian needs to assess their reliability. What is a text’s purpose? What are its sources of information? How good are those sources? How does it use the sources? What is the state of its transmission and preservation? And so on. This scrutiny, or source criticism, allows the modern student to use the available information effectively and to cope with conflicting information. A historian’s answers to source criticism questions will of course depend on his or her own purpose in writing. Our focus here is simply on the capacity of the sources mentioned above to supply the chronological backbone, so to speak, of the imperial period (for a broader treatment see Smith, this volume).
The question of purpose is basic. Sometimes an author supplies the answer, or at least an answer. Eusebius’ Life of Constantine, for example, was written as ‘‘an unstinting account of good things’’ (1.10.2), particularly of deeds ‘‘dear to God’’ that fell outside the normal scope of political and military history (1.11.1). Eusebius’ purpose is explicitly laudatory (‘‘unrestrained praises in varying words’’ 1.11.2) and the work as a whole is designed as a counterweight to the histories that record the misdeeds of emperors such as Nero (1.10.2). ‘‘Good things’’ do not include the execution of Constantine’s eldest son Crispus or the (forced?) suicide of his first wife Fausta, which are accordingly absent from the biography, though attested elsewhere (e. g. Jerome on 328 ce ‘‘Constantine killed his wife Fausta,’’ one of three entries for the year). Given Eusebius’ purpose in writing, the omission ofthese events in the Life does not in itself cast doubt on the authenticity of reports elsewhere on the deaths of Crispus and Fausta. The dedications to the emperor Valens that open the summary histories of Eutropius and Festus provide similarly helpful information (see above). Frequently, however, and particularly with full-scale histories, there is less to guide us. Reputable historians, as Tacitus tells us in the preface to his Histories, are responsible to the truth (1.1.4), not to a patron or the powerful. We would like to believe him, but at no period during the empire does a historian give evidence ofbeing able to feel what he wants and say what he feels, particularly about contemporary events. Tacitus, who asserts that such was the happy condition of the historian under Nerva and Trajan (Hist. 1.1.4), did not write about Nerva or Trajan. And Tacitus was aware that there was danger in writing even on non-contemporary events, as is shown by his extended discussion (Ann. 4.34-5) of the fate of the historian Cremutius Cordus, who died under Tiberius for his history of the end of the republic. The first question to ask, then, is whether the writer can tell the truth about an event, should he happen to know it.
The second, of course, is whether he can know it (Potter 1999a: 79-119). We do have some contemporary reports: Velleius on parts of the reigns of Augustus and Tiberius, Dio and Herodian on the reigns of Commodus and the Severan emperors, Eusebius on Constantine. Josephus was a participant in the Jewish War of 66-70, Lactantius a contemporary of the persecutions he reports in the greatest detail. Tacitus, Plutarch, and Suetonius were alive, but not yet adult, during some of the periods they reported on; they will have had access to surviving contemporaries. But contemporary evidence, even when obtainable, is necessarily shaped by the prevailing political climate, particularly in authors (e. g. Velleius and Josephus) writing about emperors who are still alive. Few did so.
Authors writing and publishing after their subjects are safely dead depended on earlier (now lost) narrative sources, sometimes a chain of such sources. If these were modern historians we would begin our assessment of their reliability by looking to the sources they cite. But generic decorum discouraged citation of sources in the historians (the biographers, as we have seen, had a little more freedom here). Occasionally Dio will cite a source by name (e. g. the memoirs of Septimius Severus at 75.7.3), but usually to challenge its information. On the victory in 197 ce for which he cites Severus, for example, he says, ‘‘my account represents not what Severus wrote about it, but what actually happened.’’ How he knows what actually happened he does not say. (Similarly for a reference to Augustus’ memoirs at 44.35.3.) More common are general references to ‘‘earlier accounts,’’ which are often occasioned by implausible or discrepant stories. On the identity of Galba’s assassin, for example, in Tacitus: ‘‘There is no agreement as to the killer. Some say it was a bodyguard named Terentius, others one Laecanius; the more common report says that a soldier of the 15th legion named Camurius applied his sword and slit Galba’s throat’’ (Hist. 1.41.3). This kind of citation does little to help us identify Tacitus’ sources. In fact this particular passage looks even less helpful when we set beside it Plutarch’s report: ‘‘The man who killed him, according to most writers, was a certain Camurius from the 15th legion. Some report that it was Terentius, others Lecaenius, still others Fabius Fabullus’’ (Life of Galba 27.2). We have to conclude that both authors took the reference to conflicting reports from their common source. The content of the statement - that Galba’s assassin was variously identified - may well be true, but there is nothing to suggest that either Tacitus or Plutarch verified it for himself. In fact, the identification of a literary source’s own sources, a procedure known by its German name ‘‘Quellen-forschung,’’ relies less on the rare specific or general references in a work than on a painstaking analysis of the content-based and thematic and stylistic ‘‘fingerprints’’ of those sources (the introductions to commentaries on historical works generally supply details and bibliography on these sources).
References to documentary information are even rarer than references to literary sources, in part for the same reasons of stylistic decorum, but also because historians of the empire were conditioned to disbelief in official records. Appian, for example, reports that in 35 bce Octavian ordered written records of the civil wars then ending (so he thought) to be destroyed (BC 5.132), thereby ensuring that his version of events had the advantage in future histories. And Tacitus, when faced with the official record of the Senate’s implicit verdict on the death of Tiberius’ heir Germanicus (natural causes, despite Germanicus’ belief, which the Senate duly records, that one Gnaeus Piso caused his death; we have a version of this document in the recently published Decree of the Senate on Cn. Piso the Elder), could see as clearly as we can that it offered not the truth about events, but rather the truth about what the Senate felt it could safely and appropriately say on that occasion (Damon and Takacs 1999: 143-62). The involvement of Piso in the prince’s death, though discredited by the Senate’s verdict, is attested in literary sources (Suet. Cal. 2, Tib. 52.3; Dio 57.9) and survived as a rumor down to Tacitus’ own day:
[Germanicus’] death was the subject of all sorts of rumors not only among his contemporaries but for subsequent generations as well. So much in the dark are we about even the most important events, since some people treat what they hear as the truth, no matter the source, and others take the truth and turn it into lies. And the stories continue to develop as they are handed down. (Ann. 3.19.2)
Tacitus accepted neither the Senate’s verdict nor the rumor, but gave both an airing in his narrative. In a similar circumstance Dio can be more decisive, since he was himself present at a Senate meeting that produced some highly dubious official documents in 205. Presented with trumped-up evidence ‘‘justifying’’ the summary execution of a praetorian prefect, the Senate issued decrees praising its authors (76.35). In fact, it was clear to all concerned that such decrees were liable to have been issued ‘‘under the influence of necessity or awe’’ (Suet. Aug. 57.1).
In general the ancient historian staked his authority, his claim to a reader’s belief, on the persona he conveyed as an author - his moral character, analytical power, and literary skill - not on his sources, literary or documentary. We prefer to have evidence, especially non-literary evidence, providing independent confirmation. Thus we believe the Historia Augusta’s unique report that Hadrian built a wall 80 miles long in Britain (HA Had. 11.2) because the troops to whom Hadrian gave the task left records of their progress, including dates and segments built, at the wall itself. Source criticism requires asking many more questions than those illustrated here, particularly when one wants to go beyond simply establishing a chronological sequence, but for these the detailed studies of the various sources for imperial history listed in the bibliography are a more appropriate venue.
World History
