A huge amount of ancient history can be recovered only with the help of Diodorus of Sicily, who wrote in the first century bce. He is our main source not just for less mainstream events that other historians ignored, but for central aspects of ancient Greek history: the history of Sicily, the career of Philip II of Macedon, and the struggles of the Successors following the death of Alexander the Great. And he is always to be consulted on every other period as well; he is, for instance, the earliest surviving historian by over a hundred years to cover the career of Alexander the Great. He importantly supplements Thucydides on the fifty years preceding the outbreak of the Peloponnesian War in 431, and often gives different versions of Roman history from the usual historians, such as Livy. Every page of The Library contains information that we would not otherwise know, and the loss of much of it is lamentable.
Almost all we know about Diodorus’ life is what can be gleaned from The Library itself. He was born in Agyrium in Sicily (1.4.4), a prosperous town at the time of his birth, and one of the older Greek settlements in the interior of Sicily, rather than on the coastline. By coincidence, of only two inscriptions that are known to have survived from this town, one is a tomb marker for a ‘Diodorus, the son of Apollonius’.1 Diodorus is not an uncommon name, so we cannot be certain that this (undated) inscription refers to our Diodorus, but it is a curious coincidence.2
We cannot be sure of the years of his birth and death, but there are clues in his work that allow us to home in on them. At 16.7.1 he says: ‘But eventually, after Caesar had expelled the people of Tauromenium from their homeland, it was made the site of a Roman colony. This happened in my own lifetime.’ This colonization probably took place in 36 bce. Octavian (the ‘Caesar’ referred to here) held a grudge against Tauromenium, which had refused to surrender to him earlier that year, in the course of his war against Sextus Pompey, and the historian Cassius Dio says that Octavian punished a number of Sicilian cities at the end of this campaign (Roman History 49.12.5). That is the latest event mentioned by Diodorus. At 12.26.1 he refers to the Rostra (public speaker’s platform) which stood ‘in those days’ in front of the Senate-house in Rome. Since it was removed by Julius Caesar in 45 bce, that bit of Book 12 was written after then. Book 37.27 refers to Caesar’s refoundation of Corinth in 44, and at 16.70.6 Diodorus refers to the blanket conferral of Roman citizenship on the Sicilian Greeks, which also happened in that year. He several times alludes to Julius Caesar’s deification, an honour that was first granted in 48 bce (1.4.7; 4.19.2–3; 5.21.2; 5.25.4; 32.27.1).
He cannot have started writing earlier than the mid-40s,3 because (see below) his original intention was to take the work down to 46 bce, choosing this end-point perhaps because Julius Caesar had by then conquered his internal enemies and pacified Rome’s external enemies, so that for the first time for decades the world seemed to be at peace. Nevertheless, he began his research much earlier. He was on a research trip to Egypt during the 180th Olympiad, 60/59–57/6 bce (1.44.1; 1.83.9; 3.11.3; 3.38.1; 17.52.6). He mentions at 1.83.5–9 that in the course of this trip he witnessed an Egyptian mob force the death penalty on a Roman official for his accidental killing of a sacred cat, despite their fear of Rome and despite the fact that ‘King Ptolemy had not yet been officially recognized as a friend of Rome’. The king at the time was Ptolemy XI, and his reign was recognized by the Romans in 59 bce. At the time of Diodorus’ visit, Macedonian rule of Egypt had lasted for 276 years (1.44.4). Since he dated the Macedonian takeover of Egypt to 331 (17.49), he is talking about 55—a minor, but not untypical, lapse in his arithmetic (see e.g. 17.17.4, 19.27.1, 20.2.3). Presumably, he spent at least some of his time working in the famous library of Alexandria,4 or as much of it as an outsider was allowed into; at any rate, at 3.38.1 he refers to ‘royal records’ that he consulted in Alexandria.
The sentence in 1.44.4 suggests also that at the time of writing, Diodorus was unaware of the end of the Ptolemaic dynasty of Egypt. As far as he was concerned, Macedonian rule of Egypt was still ongoing; if he had known about the fall of the regime in Egypt, he would have mentioned it. Its end came in 30 bce, when the last Ptolemy, Cleopatra VII (the famous Cleopatra), committed suicide. So he was either unaware of this fact, or did not bother to go back and revise this statement in his first book. Assuming the former option, and given the reference to the colonization of Tauromenium in 36, we can say that the work was published some time between 35 and 30 bce.
As was commonly the way in the ancient world, however, a certain amount of ‘publication’ had already taken place. At the beginning of the whole work, as part of the general preface that was written after he had completed the entire work, he mentions the possibility that some of the books that make it up might be ‘mutilated’ by being pirated or privately copied (1.5.2), and at the very end (40.8) he complains that, indeed, some of his work had got into circulation before the work as a whole had been completed and properly published.5 In fact, at 1.4.6 he says, oddly, that although the work is complete, it has not yet been published, which raises the possibility that Diodorus himself never published the work, and never got around to revising it before his death; otherwise, he would presumably have removed this statement from the published book. There are a lot of easily correctible mistakes in The Library, as we shall see, and the idea that it remained unrevised is an attractive one.6 Be that as it may, we can say, with some assurance, that Diodorus was researching and writing from the mid-60s to the mid-30s bce, and this chimes with his own statement (1.4.1) that the work took him thirty years.7 As a result of all this we might guess that he was born c.95 and died c.30 bce.
Despite the impoverishment of Agyrium during his lifetime, as chronicled by Cicero in his speeches against Verres, Diodorus must have had sufficient wealth to choose a lengthy career as a writer, and to have undertaken his research trips. He was upper-class enough to mingle in Egypt with high society—priests and ambassadors. It is perhaps not surprising, then, that he not infrequently displays an anti-democratic bias, typical of the wealthy elite of the Greek and Roman worlds (see e.g. 1.74.7; 18.18.8; 18.67.6; 19.1.5; 20.79.3).8 Some time after these trips, he settled in Rome (as did many other intellectuals at the time), where there were good libraries (1.4.2), and focused on library research.9
At 1.4.1 he claims to have visited much of Europe and Asia, but this seems to be an exaggeration. He shows familiarity with places in Sicily, naturally, but seems less certain about even southern Italy, and the trip to Egypt is the only one he mentions. It makes sense to think of him working primarily in the libraries of Sicily and Rome, where he stayed ‘for a long time’ (1.4.3). But if Rome was important for his research phase, it was less so when he began to put all of his notes into order and write them up; perhaps he left Rome and returned to his native Sicily.
We can infer a few other personal characteristics. His religious morality was conventional, but he believed that the gods were originally culturally important mortals who later became deified (e.g. 1.17.1–2; 1.22.2; 5.67.1).10 He had a magpie-like attraction for the exotic and unusual. He was a misogynist, as is most clearly revealed by the statement at 12.14.2 that it is better to expose oneself to the perils of sea-travel than to those of a woman, and that therefore for a man to marry twice is sheer lunacy. His praise of the constitutional kingship of ancient Egypt in Book 1 suggests that he might have been a monarchist. And, finally, we can safely say that he was hard-working and determined, otherwise he would not have begun or completed his great project.
The chances are that Diodorus’ attitude towards Rome was ambivalent. His sojourn in Rome coincided with a period of unprecedented political turmoil and violence, including the first and second triumvirates, proscriptions, rioting and murder on the streets, and two civil wars. Rome achieves no prominence in his account until well into the third century. At 37.3, he describes the Romans of his time as decadent, corrupted by imperial wealth,11 and at 32.4–5 and 32.26.2 he contrasts the decency of earlier Romans, which had gained them an empire, with the terror tactics currently employed to maintain the empire.12 His remarks, therefore, about how empires are lost by unfair treatment of subjects are certainly meant to contain a lesson for his contemporaries in Rome.
In his lifetime, much of his native Sicily was plundered by venial Roman governors and fought over by its warring generals, and Agyrium suffered in particular. While accepting the fact of Roman rule, and even (necessarily) making the unification of the Mediterranean world under Rome a major theme of The Library, he avoids the customary effusive praise for Roman might and glory, and his history may well contain a tacit lesson for Rome: that empires fall as well as rise. Diodorus believed in some version of the theory of the succession of empires (see note 29), and may have believed that the Roman empire was not necessarily the last, the final end-point of history, as many of his contemporaries believed or professed to believe. In the first three books of The Library, Diodorus focused on the ‘barbarian’ nations that Rome had not conquered, and there were a lot of them, suggesting another limitation to Roman power.
He has high praise for certain Romans, especially Pompey the Great (38–39.9–10, 38–39.20) and Julius Caesar (especially 32.27.3), but criticizes others (e.g. 38–39.8.1–4; 40.4). There is a similar ambivalence as regards Rome’s enemies, who are often portrayed as moral villains, as though it were the Romans’ duty to subjugate them, but sometimes as men of honour (e.g. Arsaces and Viriathus in Book 33). But Diodorus seems to have thought little of the Romans collectively. He commends them only for their libraries, for their military prowess, and for having driven tyrants out of Sicily (1.4.2–3; 37.1; 19.1.5). Despite his long stay in Rome, he never acquired citizenship,13 and does not seem to have gained a member of the Roman elite as a patron (otherwise, his name would have been Romanized, as a near contemporary, Diodorus of Lilybaeum in Sicily, became Quintus Lutatius Diodorus). There is no evidence that he belonged to one of the several literary circles that existed in Rome at the time, which was the usual route for a provincial intellectual to gain attention. Diodorus must have interacted with Romans—not least in order to gain access to private libraries—but he does not seem to have been taken up, as many other provincial artists and intellectuals were. He seems to have remained somewhat of an outsider in Rome.
But too much of Diodorus’ narrative of Roman history is lost for us to be certain what his attitudes were towards the mistress of the Mediterranean. We can infer what he thought about certain aspects of Roman society at the time—that he approved of Julius Caesar’s deification and thought that the Romans might benefit from a properly tempered monarchy—but these do not add up to a comprehensive stance on Rome as a whole. He certainly fell short of being a direct critic of Rome, just as he seems not to have used his writing as a platform for any other political stance, because we would know if he had gone that far. Even without the survival of any of his work, for instance, we know that Timagenes of Alexandria, a later contemporary of Diodorus, used his history-writing to criticize Rome and Augustus. It was expected that historians would use their work to comment on contemporary affairs, yet Diodorus seems largely to have avoided doing so. As far as our evidence goes, given the parlous state of the last twenty books of The Library, Diodorus comes across as a muted, apolitical historian. His Sicilian background shows in the proportion of The Library that he devotes to Sicilian affairs, but he is not otherwise a spokesman for Sicily, let alone Rome.
The title of Diodorus’ work is odd, and a novelty (later imitated by others), but he was trying to capture its most important feature—that he intended it to be in itself an entire library, a one-stop shop for information about the history of the known world.14 As a library, it naturally incorporated the work of many writers. It was, in other words, a compendium of earlier historians’ work.
This is important, because it means we should not expect more than Diodorus claims. He was not offering an original work of history, but a compilation. That was what all ‘universal’ historians offered; given the nature of their task, they had little choice. They selected from their predecessors and compressed the material. They could not carry out original research for the entirety of world history up to their time. In fact, compilation, or reliance on tradition, was the normal working method for all historians who dealt with the remote past, inaccessible to autopsy or interviews with eyewitnesses,15 and so far from discrediting Diodorus we should commend him for the honesty implicit in his title.
The prefaces Diodorus composed for each book are probably original or largely so, along with other non-narrative material,16 but a lot of the rest is paraphrase of others’ work—shaped by Diodorus, to be sure, but essentially paraphrase. We rarely have extant the exact wording of the sources on which Diodorus drew, but when we do it is clear that he rephrases and abbreviates, rather than coming up with an original, new narrative; facts are taken over from his sources, and even opinions, if they fit in with Diodorus’ own opinions.17 At 31.10, for instance, he takes over more or less entirely from Histories 29.21 Polybius’ reflections (by means of a quotation from Demetrius of Phalerum) on the passing of the kingdom of Macedon; Diodorus omits little more than Polybius’ claim to autopsy, which of course he could not include. Diodorus was not a mere copyist, as we shall see, but at times he drew heavily on his sources.
The Library occupied forty books, but only fifteen have survived down to our day. The surviving books are 1–5 and 11–20; of the rest only tatters remain. The first six books covered prehistory (history prior to the Trojan War), and the geography and ethnography of the known world, Greek and non-Greek; these first books were organized by geography rather than chronology. The lost Books 7–10 would have whisked us from the Trojan War (the start of which was dated by Diodorus to 1183 bce) to 481/0. Until the start of datable history with the first Olympiad (776–773), Diodorus structured his work by means of a web made up of generations, supposed synchronicities between events in one part of the world and another, and thalassocracies,18 but also local counting systems, such as the lists of Spartan, Macedonian, Persian, and Argive kings, and Athenian Archon lists.
Book 11 opens with the year 480/79, by which date Diodorus was employing his familiar combination of three counting systems (Olympiads, Athenian Archons, and Roman consuls), and we then have continuous narrative—the only continuous history in Greek of such a long stretch of time—year by year up until 302, the end of Book 20. Like Books 6–10, Books 21–40 exist only in pitiful fragments, paraphrases, and excerpts, but, even so, what remains of The Library constitutes the largest surviving body of work from any ancient Greek historian.19
The task Diodorus set himself—an ‘immense task’ (1.3.6)20 —was to compile a universal history, a history of the entirety of the known world from Creation down to his own day—which turned out to be 59 bce, the year of Julius Caesar’s first consulship and the start of his Gallic campaign. As far as we can tell from the remains of Book 40, the final book, he did indeed end at the year 60/59. The waters are muddied, however, since he says three times that he will cover Caesar’s Gallic campaigns, and especially his conquest of the British Isles (3.38.2; 5.21.2; 5.22.1),21 which took place after 59, and he also says at 1.5.1 that his work will end 730 years after the first Olympiad, which should be 46 bce.
Probably, especially seeing that all these passages occur in early books, his original intention was to take his history down to 46,22 thus including the Gallic campaigns, but at some point he changed his mind and effectively eliminated Caesar from his work (but did not get around to deleting from the text the statements promising a later stopping point). He may have thought that Caesar, who is mentioned a number of times in glowing terms, as we have seen, deserved a history of his own. In these turbulent times, he may have considered it dangerous (especially for a wealthy provincial) to write about contemporary events; in the surviving books, he mentions Octavian, the future emperor Augustus, who was at the heart of the violent politics of Rome in the 30s, only once, and that is a negative reference (16.7.1). His intention to end at 46 may have been derailed by Caesar’s assassination in 44, which made the world peace of 46 seem less of an ending than it had seemed before. For whatever reasons, faced with the choice of either extending or shortening his work, to find a more suitable end-point, he chose to shorten it to 60/59, which, with the dominance of the First Triumvirate, was effectively the last year of the Republic.23
Diodorus wanted his work to be useful, as we shall see. But useful to whom? To Everyman—because everyone can be influenced to be a better person (1.1.5) and many people enjoy reading history (1.3.6)24—but primarily to future leaders, who were the ones whose actions were writ large on the pages of history for all to see (and therefore imitate or avoid), and who were the ones who, if improved by the reading of history, would themselves become paradigms for yet further generations. Given current geopolitics, however, future leaders were bound to be Roman; most members of the Roman elite were able to read Greek, and since Diodorus quite often uses Roman history as a point of reference or comparison, he was certainly assuming a Roman readership.25 His very choice of Roman consuls as one of his year-counting systems points in the same direction. On the other hand, since at 34–35.33 he explains what it takes for a Roman general to be acclaimed imperator, something which elite Romans already knew, and since he wrote in Greek, he was also assuming a Greek-reading audience. Diodorus was hoping to attract a very wide readership for The Library.
Diodorus’ intention was not just to write a universal history, one that covered all the deeds of Greeks and non-Greeks alike from the beginning of time, but to improve on his predecessors’ attempts to do so. At 1.3.2–3, he says that, of those who had undertaken to write universal histories, some had failed from a geographical perspective and others from a chronological perspective. That is, some had failed to incorporate the deeds of easterners (he was perhaps thinking of Polybius, among others), others—such as Ephorus (4.1.2–3)—had failed to incorporate the earliest myths and legends, and yet others had started later or stopped earlier than they might or should have. And it is true that universal historians earlier than Diodorus had tended to start their histories where some predecessor had finished (as Posidonius of Apamea carried on where Polybius left off), without bothering to start all over again at the beginning, and, for obvious reasons, had avoided the mythological period. None of them, therefore, was a universal historian, strictly speaking.26
Moreover, in addition to improving on his predecessors’ scope, Diodorus planned to bring the whole work to completion in forty books (papyrus rolls, much shorter than a ‘book’ in our terms). Diodorus knew he would have to compress events and miss out a lot, but he thought that the usefulness of his work would be enhanced by brevity. Since universal histories are the most useful kind, and since even those who professed to have written universal histories failed to do so, Diodorus claimed to have written the only truly useful history book. A competitive spirit, the desire to improve on one’s peers and to be known for doing so, always prevailed among writers in all genres of Greek literature.
To be fair to his predecessors, we should note that Diodorus was in part the right person in the right place at the right time. Many of his predecessors lived before the campaigns of Alexander had opened up the non-Greek world and made a global perspective and the history of non-Greek peoples more feasible; long contact with the Persians in earlier centuries had gone some way towards informing the Greeks of eastern peoples and places, but Alexander’s conquest vastly accelerated the process.
Then again, the unification of Mediterranean history under the Roman empire also made it easier for Diodorus to attempt a universal history. He was contemporary with Pompey the Great’s conquest of Spain, pacification of Asia Minor, and incorporation of much of the former Seleucid empire under Rome in the 70s and 60s, and it may well have been Pompey’s (and then Caesar’s) campaigns that inspired him to write a universal history; at 40.4 he preserves a boastful inscription of Pompey’s, listing the astonishing geographical extent of his victories. It could only have been such campaigns that allowed him to write (1.4.3) that Rome’s power extended to the limits of the known world.
In short, the concept of universal history dovetailed perfectly with Roman aspirations at the time. There was even a coin, issued in the mid-70s, with the Roman people personified on the obverse, and on the reverse a globe flanked by a sceptre and a rudder, signifying Roman dominion of the world. Only a few decades later than Diodorus, the historians Pompeius Trogus and Nicolaus of Damascus composed universal histories, and Strabo tried to cover the whole world in his Geography.27 Roman imperialism was arguably a catalyst of global histories and encyclopedic literature.
This innovative idea of Diodorus’, to attempt a truly comprehensive world history, including the age of myth, and the relative brevity and accessibility of his work, guaranteed it a long after-life. Not only was it immediately popular (otherwise it would not have been pirated), but it was read and referred to by many later writers, and at some point, as we can tell from a Byzantine summary, someone even chose to extend it and take it down to the death of the emperor Augustus.28
Inevitably, it became more popular as the decades rolled by and the works on which Diodorus had based his history became harder to find, or even lost. In fact, the popularity of The Library in Byzantine times probably contributed to the process of the extinction of the earlier historians. Diodorus’ single compendium was preferred to the many originals, and as a result there was no demand for scribes to reproduce the work of the latter. Then Christian writers came to dominate the West, and they liked Diodorus’ moral streak, as well as his linear chronology, which they could adapt for their own purposes. Eusebius, for instance, the bishop of Caesarea in the early fourth century, whose lost Chronicle was intended to show that the march of historical events revealed God’s plan for the salvation of the world, had nothing but the highest praise for Diodorus, despite the fact that he was a pagan, calling him ‘a most distinguished man’.29
However, it has to be said that we are not given the universal history we were promised (at e.g. 1.3; 19.1.10). As the books translated in this volume attest (and despite Diodorus’ choice to make Roman consuls one of his three chronographic indicators), Roman history was often relegated to a hasty paragraph or two at the end of a year, containing little or nothing more than the kind of sketchy information Diodorus found in an annalistic source; and there is no Roman history at all in Books 17 and 18. He could have done better, since a basic annalistic framework of the history of the Early Republic had been laid down by Quintus Fabius Pictor, a Roman historian writing in Greek, towards the end of the third century, and Diodorus was aware of his work (7.5.4). His treatment of Rome became more thorough in later books, as it had to, since Rome came to dominate the Mediterranean, but otherwise it is inadequate. The difficulty of researching even more far-flung places such as the kingdoms of Bosporus or Bithynia may excuse the paucity of information we receive about them. The Library ends up more a history of the Greeks than a thoroughly universal history, but, even so, there are more than a few years when we are given no history of the Greek mainland.
The basic problem—apart from the fundamental impossibility of ‘giving a full account of all the events which have been handed down to memory and occurred in the known regions of the inhabited world’ (1.9.1)—seems to be that Diodorus found it easy to get distracted. Book 17, for instance, is a good account of the career of Alexander the Great (though with more thorough coverage of the earlier stages than the later), but Diodorus has allowed his focus on Alexander to push out events in the central Mediterranean altogether, and much Greek history as well, unless it was relevant to Alexander. Book 17 is a more unified product than any of the other books—it forms a kind of chronologically organized monograph about Alexander’s reign—and it is therefore easier to read, but it is not universal history. The same notion of Diodorus’ distractibility can also account for a certain patchiness of presentation: whereas Books 18 and 19 are a good blend of material from East and West, by Book 20 the affairs of the western Greeks in Diodorus’ native Sicily have squeezed out quite a bit of material about the doings of the Successors in the eastern Mediterranean. Diodorus was forced to select his material and omit a great deal, but that in itself undermines his grandiose claim to geographical as well as temporal universality.
Above all, Diodorus wanted his work to be useful. This was a standard claim of Greek historians, dating back as far as Thucydides.30 Historiography was always a form of teaching. Diodorus felt that, if he could encompass all world history within a reasonable number of books, and if he could write it all down simply and clearly, he would have written a useful book, because readers would not have to go to multiple sources, each no more than a monograph, and because he would provide a clear, connected, sequential narrative (1.3.6–8; 16.1.1–2). This clarity and ease of reference would enable readers to profit from the work more easily than they would by reading other historians. One can even say that Diodorus’ desire to be clear dictated the form of the work, because he felt that clarity would be enhanced by a year-by-year account (1.3.2, 1.3.8), with events expounded ‘topically’ (17.1.2)—that is, with the account of events in one part of the world completed before moving on to the next part of the world. He slightly qualifies this at 20.43.7, pointing out that a year-by-year account breaks up what would otherwise be a sequential narrative of, say, a single war into as many segments as there were years of warfare; but he still clearly prefers his system as the one that is most likely to be helpful to readers. Indeed, it is hard to think of an organizational system which would more readily have allowed Diodorus to display so much disparate information in an accessible fashion.
The reason history is a brilliant teacher, to Diodorus’ mind, is that one can read about the successes and failures of others, and learn from them, without having to suffer oneself (1.1.1–2; 1.1.4–5).31 The characters who appear on the historical stage are actors within their particular dramas, but they are also moral examples for future generations to emulate or avoid:
I shall mention certain men as exemplars, both because they deserve my praise and for the good it does society, so that bad men may be deterred from wicked impulses by the denunciations of history, and good men may be inspired by the praise conferred by history’s everlasting glory to aspire to high standards of conduct. (37.4; see also 15.1.1)
The mere recording by a historian of good and bad deeds deters people from wickedness (1.1.5). It follows (1.3) that the more complete a history is—that is, the more examples it offers of success and failure and of good and bad deeds—the more its educational value is enhanced, because among so many examples there will be those that are useful for every situation in which an individual might find himself. Hence Diodorus’ desire to be complete.
The particular usefulness imparted by a knowledge of history, and delivered by those who write history, is moral guidance (1.1.5; 1.2.1–3).32 For Diodorus, as for many of his peers, moralizing was one of the central roles of history-writing. Perhaps it was even the central role. He nowhere says that the purpose of history-writing is to preserve knowledge of past events for their own sake; the point is to guide future generations into the paths of righteousness and to alleviate distress. As he says at 18.59.6: ‘In a world of inconstancy and change history has the power to remedy both the arrogance of the fortunate and the misery of the unfortunate.’ At 1.2.2 we are told that history is the ‘prophetess of truth’ and ‘the matrix of education’, with the power ‘to endow men’s characters with noble integrity’.33 These are hifalutin assertions, but they are almost conventional clichés in the context of contemporary historiography. They tell us little about Diodorus himself, because all of his peers felt the same.
History has these powers by itself, but sometimes the historian has to bring out the moral lesson; that is, even if sometimes the moral lesson is merely embedded within the narrative, at other times the historian pauses for explicit comment in a digression or aside. Like his predecessors, Diodorus was therefore inclined to select the episodes he recounted, and to spin his account of them, to bring out the lessons. He gives his readers the facts as he has been able to uncover them, but he tends to linger over those which contained useful moral lessons. In our books, for instance, more space is allotted to the exploits of Thibron than one might have expected (18.19–21) because of the great reversal of fortune he encountered, and the same goes for the adventures of the imprisoned generals (19.16).
A good example of the embedding of morally evaluative terminology within the text is 19.11.4–7, where we are left in no doubt how we are supposed to think of Olympias and Eurydice; at other times, Diodorus might simply show that good men prosper (e.g. Philip II at 16.1.4 and 16.64.3; Ptolemy at 18.28.4–6), while bad men suffer (e.g. Tennes at 16.45.4). But explicit guidance by the historian is not uncommon. At 11.3.1, for instance, Diodorus chooses to name the Greeks who fought on the side of the Persians in 480, ‘in the hope that the shame here visited upon them may, by the sheer force of its obloquy, deter any future traitors to the cause of common freedom’ (trans. Green). An example from Books 16–20 occurs at 17.38.4–6, where Diodorus tells us in moral terms how to assess one of Alexander’s acts. These are only a few examples, but any reader of The Library will be struck by how often Diodorus leaves her in no doubt about how he expects her to judge historical events and people.
Diodorus was a traditional moralist. The virtues he valued were courage, piety, justice, lawfulness, kindness, clemency, moderation, and humility in the face of success (this last virtue is particularly stressed). He subscribed to the belief that the gods would punish wrongdoing and reward good people. Again, it was up to the historian to bring this out where appropriate. The most sustained case is his account of the fate of the Phocians who had committed sacrilege by stealing the sacred treasures of Delphi (16.61–4). At 11.46.4, the arrogant behaviour of the Spartan regent Pausanias after the end of the Persian Wars was responsible, according to Diodorus, not only for Pausanias’ own downfall, but for damaging Sparta as a whole, just as at 13.103.1–2 a miscarriage of justice in Athens is said to be responsible for their later falling under a savage oligarchy. Divine punishment often fits the crime perfectly, by mirroring it, and there are good examples of this in our books: 16.64.2–3; 19.103.4–5; 20.65.2; 20.70; 20.101.2–3. Examples from The Library could easily be multiplied, but the point is clear: thanks to the gods, individuals get what they deserve.
However, a slight tension arises in this theoretical framework because of Diodorus’ frequent reference to the power Fortune has over human lives, and her fickleness. Demonstration of the power of Fortune was certainly one of the principles according to which Diodorus selected or spun his material, and as a result the gods become somewhat downplayed as agents capable of affecting human lives.
How could anyone with a sense of the inconstancy of human life fail to be astounded by the way luck ebbs and flows one way and then the other? Or how could he put such trust in the power he wields at a time of good fortune that he would give himself airs as though he were not subject to human frailty? Every person’s life seems to be controlled by some divine helmsman, who makes it subject to cycles of alternating good and evil for ever. What is strange, then, is not that unexpected things happen, but that not everything that happens is unexpected. (18.59.5–6)
At 20.30.1, in one of his generalized statements about Fortune, Diodorus says: ‘It would not be out of place to note here the inconstancy of Fortune and the peculiar way in which men’s achievements turn out contrary to expectations.’ Logically, this means not just that bad men will be brought low, but even that good men could be brought low, or that (as happened to the king of Tyre at 17.47) a man might be raised up, or dashed down, without having done much to deserve such a fate in moral terms. Fortune is radically fickle; even ‘hopeless cases’ (20.70.2) can change under her influence. If so, then, presumably, bad men might prosper. But, if Fortune is so powerful, what happens to divine justice, which is supposed to ensure that bad men do not prosper?
It seems to me that Diodorus’ thinking on this is not perfectly consistent. When he attributes something to Fortune, it is often no more than a way to say that a person met with bad or good luck—with factors beyond his or her control. Where Fortune is more thoroughly anthropomorphized, so that she can be proactive, she rarely subverts the justice of the divine order, and in fact ‘Fortune’ is often little more than a way to say ‘the divine’ or ‘the gods’. At 19.11.6–7, for instance, it is Fortune who sees that Olympias is punished as she deserved. But there are occasional cases where Fortune seems to act against divine justice. At 17.101.2 she lays low a good man who was not deserving of such treatment. At 17.35.7 she is responsible for the rape of innocent women. At 17.46.2 it is suggested that Fortune might be envious of a man’s success and therefore see to his downfall—perhaps as she did Memnon at 17.29.4. So Diodorus has not fully made up his mind whether Fortune is a colleague of the gods or such an independent agent that she can even go against their wishes.
Apart from utility, a second and secondary intention of Diodorus was to entertain his readers. This is a subsidiary purpose because it is only meant to make the narrative more palatable and therefore more easy to understand and profit from. Entertainment comes in many forms in the pages of The Library—though there are many who might say that he should have embellished his plain narrative even more. Typical forms of entertainment are ethnographic asides, curiosities, and portents (e.g. 16.26; 17.7.5–7; 17.41.7; 17.105.1–5; 17.107; 17.116; 19.33.2–4; 19.98–9; 20.14.6; 20.58.2–5); the description of awesome structures (17.115; 18.26–7; 20.91.2–8); and the vivid and even sensational presentation of scenes (e.g. 17.13; 17.35.5–7; 17.58.5; 17.69.2–9; 17.92; 18.31.2–5; 20.51.3–4; 20.72.2–5), for which he sometimes even underlines the vividness by saying ‘the scene before a spectator’s eyes would have been . . .’ (17.25.4; 17.34.1; 19.7.2–4). Invariably, in these cases, the reader’s responses are guided by Diodorus, when, for instance, he allows the pathos of a scene to deliver the moral message. He relishes surprises, reversals, and unusual events in themselves, but also because they show the fickleness of Fortune and therefore suggest the need to be humble in the face of success (e.g. 17.5.6; 17.28; 17.46.6–47; 17.86.3–6; 17.100–1; 17.103.7–8; 20.13.3–4; 20.25.4).34
Many of these passages are examples of good writing. Analysis of the text has shown that the style in which it is written is pretty uniform throughout, and that it is the late Greek one would expect, rather than the earlier Greek used by his sources.35 He was clearly rewriting as he paraphrased, and this means that we can attribute the good and bad points of style in the text to Diodorus himself. As one reads him, one gets the impression that he was not a confident writer, but he is always clear enough, and frequently very readable. The ninth-century Ecumenical Patriarch of Constantinople, Photius, summed up his style well: ‘His style is clear, unadorned, and particularly suitable for history. He overuses neither Atticisms nor archaisms, but neither does he descend to the level of everyday language; he finds a happy medium between the two.’36
It is easy to detect his faults as a writer—a flatness of tone, repeated formulaic phrases, the relentless emphasis on warfare—but he is not uniformly dull or even plain. He knows, for instance, how to use short bursts of direct speech for dramatic effect (16.43.4; 16.87.2; 17.54.4–5; 17.66.5; 18.60.6; 19.97.3–5), although he largely eschewed the extended speeches beloved by most other historians (20.1–2.2). He throws in the occasional rhetorical question (e.g. 16.9.2; 18.59.5). His battle scenes—and battles loom large in The Library—are often thrilling, if somewhat formulaic: battles are invariably ‘tough’ or ‘hard-fought’ or ‘fierce’; the outcome often hangs in the balance for a while, before Fortune, often using a single individual as her instrument, decides the issue. He was very aware that a work of literature should have what he calls ‘proportion’, by which he seems to mean that the length of a piece of narrative should reflect the importance of the events being narrated, and that a writer should not indulge in long set pieces (in our books, see the preface to Book 20, but then e.g. 1.9.4, 1.29.6, 1.41.10, 4.5.2, and 4.5.4). He likes neat, moralizing conclusions, such as ‘Persepolis had exceeded all other cities in prosperity, and now to the same degree it exceeded them all in misery’ (17.70.6), or ‘Iniquitous behaviour may profit rulers because they can get away with it, but for ordinary people, their subjects, it generally leads to disaster’ (19.48.4), or ‘For the common people never like it when things stay the same, and every group that is not dominant finds change attractive’ (19.81.3). The Library is not a difficult read, and its plainness is arguably not a fault in a historian.
It used to be the fashion to say that for long stretches of his work, even whole books, Diodorus followed only a single source and used him rather uncritically (so that much of Books 11–15, for instance, might be considered a lengthy ‘fragment’ of Ephorus of Cyme). This rather uncharitable view has given way in recent decades to the idea that, for any stretch of his work, Diodorus relied on a variety of sources (though often one main source) and created a patchwork narrative out of them, exercising a degree of originality and creativity in deciding what to include or exclude, in shaping the material, and in imposing his moral concerns on it. The early books are better examples of this than those translated in this volume, because in the early books Diodorus was faced with a vast mass of unorganized material from a great many sources, and had to work harder to impose order on it.
Diodorus’ words at 3.11.2 are very telling: he distinguishes Agatharchides of Cnidus, Artemidorus of Ephesus, and other unnamed writers as more accurate than others who, he says, relied on false reports or even made things up themselves. This shows not only that he could approach his sources critically, but also that he relied on more than one source—here Agatharchides, Artemidorus, and the unnamed others. At 1.56.6 he says that he will record the different views of historians ‘so that readers may judge the truth with an open mind’. At 20.79.5 and 20.89.5, it is clear that he has consulted Timaeus of Tauromenium along with several other sources for Sicilian history.38 At 2.32 he goes so far as to give us two different accounts of an episode, each from a different historian he had consulted. He often refers to what ‘some [unnamed] historians say’ (e.g. 16.56.7; 17.23.1; 17.65.5; 17.73.4; 17.75.3; 17.117.5; 20.13.1), and it would be sheer lack of charity to think that he took even such phrases over unthinkingly from his sources.
Sometimes the joins between different sources are visible, thanks to near contradictions. There are plenty of examples of this in the books translated in this volume. The portrait of Philip II in Book 16 is invariably highly positive, for instance, but once in a while, when he is following another source (perhaps Theopompus of Chios), a different picture emerges (e.g. 16.87.1). The most telling case is at 16.54.4, where we are lucky enough to have the alternate source on which Diodorus was drawing—a famous speech by Demosthenes—and we can see how Diodorus has been influenced by Demosthenes to give a less than positive account of Philip, as a corrupter of men’s morals, whereas otherwise one of the threads of the book is how Philip was rewarded by the gods for his piety. Similarly, in Book 17, Diodorus’ invariable praise of Alexander yields once in a while (e.g. 17.79–80; 17.84) to a less flattering portrait. Again, we see indications that Diodorus did not thoroughly revise the work, otherwise he would presumably have ironed out such contradictions.
At 16.14.3 and 16.30.1, Philomelus is said to have plundered the sanctuary at Delphi, which is denied at 16.28.2 and 16.56.5. At 18.33.1, Diodorus says that news of Eumenes’ successes in Asia Minor reached Perdiccas in Egypt, but at 18.37.1 he (correctly) says that the news did not arrive in time. These are examples of Diodoran carelessness (on which more below), but they also show that he was not merely copying from a single source. In Book 18, praise of Ptolemy occasionally (18.14.1; 18.28.5–6; 18.33.3; 18.34.2–4) intrudes into a narrative that otherwise avoids such effusion. At 18.59.3 the commanders of the Silver Shields display considerable loyalty to Eumenes, but at 18.60–1 Eumenes is doubtful of their loyalty.39 In Book 19 we are given two rather different portraits of Seleucus, one in which he stands in Antigonus’ shadow (19.12–48) and one in which his leadership is emphasized (19.49–92). Since Hieronymus of Cardia, Diodorus’ primary source for Successor history in Book 19, wrote in the Antigonid court, the anti-Antigonid material of the second half of the book must come from elsewhere, perhaps Duris of Samos. At 19.9.6 Diodorus fails to reconcile the two different portraits of Agathocles that he received from his sources—the bloodthirsty tyrant or the benevolent king.
It is clear that Diodorus was not merely copying from a single source. He was more eclectic and better read than some scholars still allow him to be; he made use of multiple sources, or perhaps on occasion one main source garnished by pickings from others. He also approached them critically; let one more example stand for many. At 17.113.2, Alexander the Great has returned to Babylon and embassies from all over the known world come to honour him. We know that Cleitarchus, Diodorus’ presumed chief source for Book 17, included a Roman embassy (FGrH 137, F 31), but Diodorus sensibly omits it. He does not argue against it, as Arrian does (The Expedition of Alexander 7.15.5–6), because as a universal historian he cannot allow himself the space to do that; so he just tacitly omits it.
Everyone agrees that Diodorus omitted a great deal of the material that he found in his sources; he had to, in order to fit everything that he wanted to cover into forty books. But any writer, when he omits something, takes care to paper over the cracks as much as possible. Omitting a certain event means that all traces of that event in future years must be omitted as well, along with any run-up to it in earlier years, and that its connections with the events immediately surrounding it have to be disguised. The Library usually reads coherently, and that is a sure sign that Diodorus put in considerable work to shape his material. A good example of this is that in his battle scenes he often brings out the suffering of the civilians involved, the horrors of war, and the bravery of the underdogs, in order to tinge the accounts with a moral flavour. He does this so consistently, whatever sources he is drawing on, that it is safe to conclude that much of it is his own work.40
At least some of Diodorus’ moralizing was given to him by his sources; the moralizing tendency is very pronounced in Greek historiography in general. The uniformity of the morality throughout The Library shows, however, that, even where Diodorus took over the moral to a story from one of his sources, he did so only when it was compatible with his own beliefs. He stamped the material he inherited with his own concerns. Here are a couple of slight but telling examples. First, as far as we can tell, Ephorus described the fifth-century Athenian empire as, among other things, ‘very upright’ (FGrH 70, F 191); Diodorus took over the other adjectives from Ephorus, but changed ‘upright’ to ‘clement’ or ‘equitable’, which is one of his preferred terms of commendation. Similarly, comparison with Plutarch, Nicias 28.2 suggests that Diodorus changed the original (Timaeus was the source common to Plutarch and Diodorus) from ‘a noble use of victory’ to ‘a merciful use of victory’—mercy, like clemency, being a virtue Diodorus rated highly in leaders.
These are rare cases, however, where we have a means of checking the actual wording of one of Diodorus’ sources, and therefore of assessing the extent of Diodorus’ copying or creativity. Usually, all we have to go on is the fact, already mentioned, that stylistic analysis of the work reveals a uniformity that can only be explained by the hypothesis that Diodorus made all the material he inherited his own and wrote it up in his own way. Of course, some words, phrases, and even sentiments have been taken over from his sources, but it is clear that Diodorus was no mere scissors-and-paste writer, otherwise there would be more variety to his work; he has imposed his own style on it.41
Above all, the work has an overall intellectual unity, as we might call it; the consistency of the views expressed throughout The Library show that Diodorus introduced his own concerns, rather than slavishly taking over every detail or opinion from his sources. Diodorus’ views on the utility of history, on the role of Fortune in getting men to avoid arrogance at times of success and to take heart at the times of trouble, and on how power and empire are perpetuated by fair and moderate treatment of subordinates and lost by the opposite, are all independent of his sources.42 These were his overriding concerns, and they form the threads that tie The Library together.
Diodorus, then, paraphrased material from his sources, but was no mere copyist, because he imposed his own language and views on the material. That is about as creative as any compiler can be, and there is little reason to criticize him for not having done more. He certainly thought like a historian. He was aware of the importance of autopsy (3.11.3), and presumably therefore regretted that this was out of the question for him where most of his material was concerned. The number of times he summarizes or quotes inscriptions (over forty in the surviving books and fragments) shows that he was aware of their importance for the historian. Despite his emphasis on proportion (above, p. xxviii), he allowed himself to give detailed accounts where he felt that the material was interesting and informative, ‘in order’, as he said at 4.46.5, ‘that nothing which is relevant to this history of mine may remain unknown’. He was aware of the importance of giving context to make his account more comprehensible (e.g. 18.5.1) and worried that his annalistic system might jeopardize that clarity (20.43.7). His cross-references are on the whole useful and accurate. He carried out his enormous task with diligence and organized the material well. He was well read in the earlier historians and read them critically. He is not to be criticized for including tall tales and myths in the early books; he was aware of their unreliable nature (1.5.1; 4.1.1–3, 4.8.1–3), but chose to include them for the sake of completeness. The border between myth and history was not as rigid in ancient times as in ours.
Nevertheless, it remains true that Diodorus’ practice too often fails to live up to his or any other historiographical ideals. People are the focus of his history, and events are invariably due to their personal qualities, rather than to more objective causes—but then almost all the Greek historians wrote this kind of ‘Great Man’ history, and in any case, in our books, great men such as Philip, Alexander, and the Successors were largely responsible for events. There is too little politics in his work; we are given largely military narrative, but little of the political background or aftermath to the wars and battles. At 16.38.1, for instance, we read: ‘Once he had completed the reorganization of Thessaly, he advanced to Thermopylae to fight the Phocians.’ The military information is beyond price—but we would also dearly like to know how Philip reorganized Thessaly. Diodorus apologizes for his digressions—they ‘demand to be told’ (e.g. 17.27.7)—but we wish there were more.
Apart from these general criticisms, there are many minor deficiencies in The Library, which cumulatively do considerable damage to the value of Diodorus’ work. Above all, there are frequent problems with his chronology. We need to remember that he was trying to do something very difficult. He was not only trying to coordinate the various accounts he found in his sources, but he was also trying to structure his work by means of three different dating systems—Olympiads, Athenian Archon years, and Roman consul years.43 The reason this was likely to cause problems is that while Athenian Archon years and Olympiads began fairly close to each other after the midsummer of a year, Roman consuls took power on 1 March (in our terms), that is, at the beginning of a campaigning season.44
This linking of two incompatible systems not infrequently tempted Diodorus to write as if the consuls took office at the same time as the Athenian Archon, and therefore to assign all the events of a campaigning season, from spring to winter, to a single Archon year, when an Archon year began in July, not in the spring. Although in theory he could have bundled the events of a consular year with either the preceding or the succeeding Archon year, he tended to do the latter. This is his single most common fault. Here are a couple of examples from our books. We know from elsewhere that it was in the spring of 302 that Lysimachus crossed from Thrace to Asia Minor for the campaign that would culminate in the battle of Ipsus in 301. At 20.107.2, however, Diodorus places the crossing in the year 302/1—a clear case of a spring event being bundled together with the following Archon year. We know that the debate over the succession after Alexander the Great’s death took place in June 323, before the beginning of the next Archon year, but in 18.2 Diodorus includes the debate among the events of 323/2.45
The difficulties were exacerbated by the different chronographic indicators that Diodorus found in his sources. Some histories were structured by the astronomical phenomena that determined the seasons—the rising or setting of a star, for instance. Or his sources might use a framework based on the campaigning season of each year, in which armies took to the field in spring and broke up for winter quarters late in the year, effectively structuring their histories by solar years. Plainly, any historian employing such a structure would have no need to interrupt his narrative in order to indicate the change-over of Athenian Archons, so Diodorus could only guess at which point in the narrative that happened. All this made it more difficult for him to assign events correctly to each year. In Book 17, the slippage becomes so great that events are misdated by as much as three years. I suspect that Diodorus was aware of the problems, and that is one reason why he makes very frequent use of lamentably vague phrases indicating intervals of time—phrases such as ‘meanwhile’, ‘next’, or ‘some time later’.
Some events are summarized from start to finish under the heading of a single year, when they plainly lasted longer than a year. An innocent example of this is when he announces that a ruler came to power and then says, ‘and he ruled for n years’. It is more misleading, however, when complex events are summarized in this way, making it impossible for us to place them accurately within the n years that are being summarized. In Book 16, for instance, the account of the Third Sacred War, begun in 355/4 and assiduously detailed under the headings of subsequent years, breaks off after 352/1 and resumes in 347/6, with the action of the intervening years summarized prospectively under 352/1 and retrospectively under 347/6 (and inadequately in both cases). Or again (a notorious case), the entirety of the exile of the famous Athenian statesman Themistocles is covered within a single year (11.54–8, in the year 471/0), despite the fact that it went on for several years. Examples could be multiplied.
It is right to criticize Diodorus for being sloppy with dates: chronology is, after all, one of the fundamentals of history. There is of course a lot more to history than dates, but alongside errors of chronology, the pages are also littered with errors of fact. In Book 20, for instance, he is undecided whether Agathocles’ son is called Archagathus or Agatharchus; at 20.73.1 he writes ‘Phoenix’ instead of ‘Philip’ as the name of one of Antigonus’ sons, and at 16.32.1 he wrote ‘Eudemus’ instead of ‘Thoudemus’; at 16.53.2 he seems to think that the Chalcidice peninsula is near the Hellespont; at 16.93.9 Attalus is said to be the nephew rather than the uncle of Cleopatra; at 16.72.1 the Illyrian king is said to have died, when in fact he was deposed, but remained alive; in Book 17, a man whose name we know from elsewhere to be Abisares is called variously Embisarus (17.87.2) and Sasibisares (17.90.4). And so on: these and other mistakes (e.g. with his arithmetic) are pointed out in the Explanatory Notes. No doubt some of them are due to his sources rather than to Diodorus himself—but that only shifts the blame from carelessness to a lack of thorough research. We should also be aware of the way Diodorus probably wrote The Library; it would have been perfectly normal for him to have dictated the work to an educated slave, and some of the mistakes might be due to the slave’s carelessness, not Diodorus’, even though he still clearly failed adequately to revise the work. Perhaps he was slipshod, but I prefer to think that he was overtaken by death or incapacity.
There are also surprising omissions: the signing of the Peace of Philocrates between Philip II and the Athenians; Alexander III’s birth; the formation of the League of Corinth; Alexander IV’s birth; the Roman defeat at the battle of the Caudine Forks in 321—to name just a few. Any writer who has set his hand to a general history knows the painful decisions of omission and abbreviation that he has to make, but, even so, some of Diodorus’ omissions seem ill chosen. Another form of omission consists of anacoloutha and non sequiturs—places where the information Diodorus gives us is isolated, with either no lead-in or no follow-up. 18.14.4 is a good example of the latter. We are told that Lysimachus and Seuthes were preparing for a final, decisive battle, but we never get to hear about it. At 16.25.1 the Boeotians send troops into the field to combat the Phocians, but we subsequently hear nothing more about them. At 17.71.7 we are told that a mountain was ‘four plethra away’, but we are not told what it is four plethra away from. At 18.23.4 Diodorus talks of ‘the Athenian ships’ as if we knew what ships they were, when they have not been mentioned earlier. At 18.38.1, the same happens with an agreement between Perdiccas and the Aetolians. There are occasional unfulfilled cross-references.
There are quite a few doublets in the text, where an event is covered more than once, with the inherent danger of confusing readers about which year it belongs to. Most of these are relatively innocuous, in that he merely mentions an event in a summary fashion at one point and then gives an account of it later; 18.73.3–4, for instance, is a summary of the action of 19.12–13. Doublets which actually repeat narrative are fortunately more rare—as at 16.24 and 16.28, or 16.25.1 and 16.30.1. The doublet of the siege of Methone in 16.31 (under 353/2) and then, in more detail, in 16.32 (under 352/1) is telling. Presumably, the siege ran over the year-break, so Diodorus found a mention of it in his sources under both years. But his common practice was to bring a simple event to a close at its first mention, and that is what he did in 16.31; his only mistake was to do it again in 16.32. For all we know, some of these doublets may be due to his sources—Ephorus certainly had the habit of repeating information—but, even so, Diodorus could have made things easier for his readers.
Leaving these faults aside, Diodorus has often been accused of more serious lapses, of a kind that would suggest great carelessness. The books translated in this volume have been held to contain such serious lapses, and a short discussion of two notorious cases will not be out of place.
First, the ‘misplaced winter’ of Book 19. At 19.68.5 and 19.69.2, under 314/13, we read of two armies going into winter quarters. This must be the winter of 314/13, then. Then at 19.77.7, under 312/11, we read about an army (the one of 19.69, as it happens) going into winter quarters, and we naturally take this to be the winter of 312/11. However, at 19.89.2, still under 312/11, we hear about another army being split up for winter quarters. Since no winter has been mentioned for 313/12, scholars have tended to think that Diodorus made a mistake, and that the middle winter, the one of 19.77.7, must be the unmentioned winter of 313/12. This, of course, had major consequences for the dating of events. But there is really no reason to think that Diodorus has made a mistake. The army that goes into winter quarters at 19.77 is that of Antigonus, and the one that goes into winter quarters at 19.89 is that of Cassander. It is more charitable to assume that they both refer to the winter of 312/11 and that Diodorus has been narrating two parallel campaigns that took place in that year.46 It is not a problem that he has not mentioned the winter of 313/12, because he very often does not mention winters; they are just one tool in his chronographic box.
Second, the ‘missing Archon years’ of Book 18. At 18.26, we get Diodorus’ usual chronographic indicators—the Athenian Archon and the Roman consuls—for the year 322/1. The next such indicators occur at 18.44, for the year 319/18. Two years have been omitted, or at least the chronographic indicators for these years have been omitted. Again, it has been usual to accuse Diodorus of a terrible lapse of concentration. But it is far more likely47 that some original material has dropped out of our manuscripts. At 19.3.3 and 19.10.3, Diodorus says that he included in Book 18 an account of Sicilian history. There is no Sicilian history in Book 18, and it will by now surprise no reader to learn that Diodorus has been accused of carelessness. Surely, it is a more economical thesis, given the missing Archon years as well, to think that there is a lacuna—that our manuscripts have accidentally omitted a chunk of material, as they do also between 17.83 and 84 (see pp. 148–9). Diodorus is very careful to include the Archon names, since this was his fundamental indicator, so their omission through carelessness would be surprising. Book 18 is also noticeably shorter than other books, again pointing to a considerable lacuna. We can only guess what other material it might have contained.
So we can rehabilitate Diodorus to a certain extent, but he does make mistakes, and these faults are disturbing chiefly because he is often our only source for events. We can check in some cases—but what about all those many events and episodes where we have no external means of checking? We have to trust Diodorus, but he does not inspire complete confidence.48 But many of these faults are correctable, and in any case they affect only a small proportion of The Library; on the whole he can be confidently used as a basis on which to reconstruct the histories of the peoples and states he covers.