In 1609, the great Huguenot scholar Isaac Casaubon presented his Latin translation of Polybius’ Histories to his royal patron, King Henri IV of France. In the elegantly couched dedicatory preface, which placed much emphasis on history’s didactic and moral functions, the learned philologist argued that, of all the ancient historians, Polybius was the most edifying and enlightening on matters of state — and thus the worthiest of examination by the ruler of a seventeenth-century great power with revived pan-European ambitions. Polybius’ august predecessor and fellow writer of contemporary history, Thucydides, was certainly great, but the Athenian’s prodigious talents, Casaubon suggested, had been stymied by the geographically-circumscribed scope of his analysis — which revolved principally around Greece, and, to a lesser extent, Sicily. ‘He was therefore not provided,’ Casaubon contended, ‘with material fully commensurate to his (remarkable) abilities.’ Polybius, on the other hand, had painted on a canvas of truly epic proportions, personally bearing witness to a series of system-shattering events, from the destruction of Carthage to the final subjugation of the Hellenistic world. In so doing, he had provided future generations with the only reliable account of Rome’s rise to hegemony over the Mediterranean — or over what he famously refers to in the opening passage of the Histories as the oecumene — the entire ‘civilised’ world. And indeed, Polybius lived a truly remarkable existence — as a soldier, statesman, captive in exile; a close friend and counsellor to some of Rome’s most powerful men; and, of course, as a historian. It is perhaps not surprising that one of the figures Polybius seems to have identified most with was the peripatetic Odysseus, a man ‘well versed in wars of men and grievous storms’ whose intellect, restlessness, and general roving curiosity he evidently deemed inspirational.

Polybius was born around 200 BC in the town of Megalopolis into an aristocratic family of some repute. At the time, Megalopolis was part of the Achaean Confederation, a grouping of Greek city states which, along with the Aetolian League in north-central Greece — had coalesced to counterbalance the might of a revitalised Macedonian monarchy. Polybius’ father had served as the strategos — or top elected official — of the Achaean confederation several times throughout the 180s BC, and in 170 BC Polybius was elected, at the youngest possible age, as hipparchos, or cavalry commander, the second-highest office in the confederation. While in office, he struggled to preserve a modicum of Achaean autonomy, gingerly walking a fine line between nominally supporting Rome’s war efforts against Macedon, and a tacit policy of military neutrality. This quest for an awkward equilibrium cruelly backfired when, at the end of the Third Macedonian War, he was accused of anti-Roman conduct (most likely denounced by one of his Greek political rivals) and unceremoniously bundled, along with about a thousand other Achaeans, onto a ship bound for Italy. Perhaps partially due to his elevated social status, he developed a close relationship with the sons of Lucius Aemilius Paullus, the consul whose legions had ground down the Macedonian phalanxes at the battle of Pydna in 168 BC. They eventually intervened on his behalf, enabling him to remain in Rome rather than eke out his existence in a dreary rural backwater like so many of his fellow Greek captives. Polybius would come to establish a particularly close, quasi-paternal, rapport with the Paullus’ second son, Scipio Aemilianus. The latter would eventually rise to become one of Rome’s most celebrated statesmen, serving twice as consul and personally overseeing the final destruction of Carthage. In the Histories, Polybius tells us that ‘their acquaintance took its origin in the loan of some books and conversation about them,’— suggesting he may have early on fulfilled something of the role of tutor, before claiming that he and the younger Roman came to ‘regard each other with an affection like that of father and son, or near relations.’

Polybius’ position within Scipionic circles provided him with easy access to key political players, both Roman and foreign, for his eyewitness interviews — a process which, he repeatedly belabors in The Histories, lay at the heart of his methodological approach. In addition, he appears to have been granted far greater freedom of movement than most other exiles, and these peregrinations allowed him, in turn, to engage in the in-depth field work and topographical surveys he deemed equally indispensable to the work of a good historian. Indeed, evidence would suggest that in addition to accompanying Scipio Aemilianus to Carthage, Polybius also traipsed across Italy, most likely visited Spain and Gaul, and was even granted permission to embark on a short journey of discovery along Africa’s western shores. And yet for all these relative advantages and comforts, he could never afford to forget that he ultimately remained a political detainee at the mercy of a ruthless great power’s whims — akin, Cato the Elder reportedly once mockingly said to his face, to an Odysseus nervously tiptoeing his way around a slumbering cyclops’ cavern. Threaded throughout The Histories, the perceptive reader can thus detect a certain wistful melancholy; a quiet desperation over the slow suffocation of Greek liberties; and a creeping moral pessimism about Roman imperialism’s trajectory. The very hybrid quality of Polybius’ experience — as a prisoner-cum-insider of Rome — lends his Histories their singular quality, reminding one — in their gimlet-eyed attention to detail — of other, later studies of rising powers penned by insightful foreign observers — from Montesquieu’s incisive disquisition on eighteenth-century England’s constitution, to Alexis de Tocqueville’s magisterial On Democracy in America.

It was over the course of his seventeen years of captivity that Polybius set to the monumental task of writing his history of Rome’s meteoric rise to prominence. As stated in his introduction, he initially intended to cover the period from 220 BC — the beginning of the so-called Social Wars (220 BC—217 BC) in Greece — to 167 BC and Rome’s victory in the Third Macedonian War, which in his mind marked the final and definitive subjection of the patchwork of feuding Greek statelets to Roman primacy. Like many a scholar entangled in the thickening web of his own research design, Polybius soon realised he needed to revise the scope of the project, reaching both further back and further forward. The final version of The Histories thus commences in the years leading up to the First Punic War (264-241 BC), coming to a suitably climactic end a full 120 years later, with the grim annihilation of both Carthage and Corinth in 146 BC. Not only was Polybius a direct eyewitness to the sack of Carthage, he also claims to have interviewed ageing survivors of the Second Punic War. As a point of comparison, Livy, our other major source on the Punic Wars, wrote under the reign of Augustus, 150 years after the end of the Third Punic War.  Somewhat intriguingly, in the case of Polybius’ magnum opus, we may be dealing with a rare case of ‘live history’ : there’s a possibility, given his histories were serialised, that some of the lead Roman protagonists of the Third Punic War were already intimately familiar with his writings on the earlier conflicts with Carthage.

The Histories were undeniably a mammoth achievement — they comprised forty volumes of which five books survive in full, another (perhaps the most historically influential, the famed Book VI) almost complete, along with portions, some still quite extensive, of other volumes. Despite its relative fragmentation, the Histories is considerably longer than anything either Herodotus or Thucydides have bequeathed to us. And to further emphasise Polybius’ Herculean productivity, in addition to the Histories, he composed a eulogistic biography of his Achaean compatriot and political hero, Philopoemen, a study of the Numantine war in Spain, a work on military tactics, and possibly a separate monograph on geography. All, however, unfortunately lost.

Although Polybius was widely appreciated in the ancient world, with towering figures such as Cicero and Livy praising him as ‘a particularly fine author,’ and one ‘who deserves great respect,’ his influence arguably reached its apogee in the wake of his rediscovery in early fifteenth-century Florence. Polybius came to be viewed not only as a precious source of knowledge on the Punic and Macedonian Wars, but also as an invaluable guide to ‘prudence’ in statecraft and, perhaps most importantly, to effective military strategy and organisation. With his lengthy, technical digressions on issues ranging from fire-signalling to regimental spacing, Polybius, as the great twentieth-century classicist W. Kendrick Pritchett rightly observed[ILR3] , can be justly considered the finest ‘military historian of not just Greece but of all of Antiquity.’ He was certainly the most influential in the early modern era, with annotated translations of choice sections of the Histories soon mushrooming across the courts of Europe, and inspiring many of the landmark military reforms of the House of Orange.

Polybius’ most significant and lasting legacy, however, lies in the realm of political theory. Like most Greco-Roman thinkers prior to the advent of teleological Christianity, he understood time as circular rather than linear. Drawing on an organicist vision of politics that can be traced back to the pre-Socratic age, Polybius argued that nations were ensnared within a quasi-biological cycle of growth and degeneration from which there was no escape. There are two agencies ‘by which every state is liable to decay,’ he famously averred, ‘the one external, and the other a growth of the state itself.’ There could be no ‘fixed rule about the former,’ but the latter was a ‘regular process.’ His concept of anacyclosis; a complex process that unfolds as a politeia rotates through three separate conditions — monarchy, aristocracy, and democracy — along with each of their corrupted forms (tyranny, oligarchy, and ochlocracy, or mob rule), was deemed hugely compelling, and its intellectual vestiges can be found strewn across the historiographical frameworks of thinkers as varied as Hegel, Marx and Toynbee.

In one of the more remarkable passages of the Histories, the aristocratic Achaean compares the masses to an ocean, whose seemingly placid surface could, in a mere instant, be whipped up by a ruthless demagogue into a raging squall. Such politically destructive tempests could not be avoided, but they could be delayed. Indeed, in Book VI, Polybius famously argued that Rome’s unique constitutional compound, alloyed from the more untarnished elements of all three principal forms of government, had—at least temporarily—shielded it from the oxidising process of anacyclosis. For the historian, great power competition was fundamentally a two-level game, and Rome’s imperial success was directly linked to the solidity of its internal political arrangement, which — by combining elements of all three systems of government (democracy in elections; aristocracy in the senatorial class; and monarchic in the considerable powers granted to consuls) — maintained it in a state of delicate equilibrium, ‘like a well-trimmed boat.’

To say that Polybius’ theories on the virtues of a mixed constitution with checks and balances were impactful would be an understatement. Over the course of the centuries, they decisively shaped the writings of — among others — Machiavelli, Montesquieu, and the American Founding Fathers. As some American colonial historians have noted, Polybius was probably the most referenced of all Greek political theorists by the so-called Framing generation. John Adams, especially, was an ardent admirer, citing him extensively in his Defense of the Constitutions of Government of the United States of America, published in 1787.

Rome’s social cohesiveness, in addition to its political stability, claimed Polybius, provided it with the necessary reservoirs of resilience to weather its enormous losses during the Second Punic War, as well as an early series of crushing defeats. Patriotic unity in the face of misfortune, he argued, was preserved through the shared memory of the ‘discipline of many struggles and troubles,’ and by the ‘light of experience gained in disaster.’ Indeed, some of the more interesting passages in the Histories deal with collective memory, the importance of strong, shared civic traditions and rituals, and the perils of strategic amnesia. For Polybius, it was only when a state’s elites had a clear memory of past sacrifices, and of the efforts that had led to the construction of a political order, that they were capable of mustering the will to act in defence of that same order. The recording and preservation of the past — along with the dedicated historians who served as the Roman politeia’s guardian of its collective memory — were thus vital to provide transgenerational political stability. In many ways, when US president Ronald Reagan warned that ‘Freedom is never more than one generation away from extinction,’ he was, whether knowingly or unknowingly, channelling a long, and distinguished, Polybian intellectual tradition.

How, however, might a close reading of Polybius be of more immediate use to contemporary students of applied history and grand strategy? The Achaean historian, one can argue, remains of enduring educational value for four main reasons.

I

The first, and most obvious, is that his works constitute by far the most reliable and granular repository of information on the Punic Wars — some of the earliest and best-documented examples of a bipolar, protracted, and genuinely cross-regional great power competition.  At a time when strategists and defence scholars are focusing more intensely on both the mechanics of protracted, attritional conflicts and on the grim global ramifications of a US-China confrontation, Polybius’ relevance appears bluntly self-evident. And despite the occasionally crabbed character of his prose, which, one classicist quips, sometimes has the unadorned dryness of a memorandum hastily dispatched from a Hellenistic chancellery, The Histories make for a truly gripping and entertaining read. Much of this has to do with Polybius’ meticulous attention to detail, and with his famously nuanced approach to the study of human decision-making — an altogether rare combination of intellectual subtlety and psychological sensitivity that he shares, for instance, with his great Athenian forebear, Thucydides.  Scipio Africanus, along with Scipio Aemilianus, are perhaps the closest figures to being genuine heroes in Polybius’ narrative. Otherwise, the great bulk of his lead protagonists, ranging from Hannibal to Philip V of Macedon, appear riddled with complexities, contradictions, and foibles. In his mind, most human beings are ‘multiform,’ i.e. protean and pliable, susceptible to the pressure flowing either from events or from members of their entourage. The personality of someone such as the sphinx-like Vladimir Putin, for example, is hardly set in stone — it will evolve (or devolve) over time in accordance with external circumstances, and with his own growing hubris and mental deterioration.

For as Polybius somewhat jadedly notes:

The fact is that people’s minds vary as much as their bodies. This not only explains why the same man may be talented at certain activities and backward at others, but also why the same person often exhibits extremes of intelligence and stupidity, or of daring and timidity in comparable situations.

It is worth noting, in passing, that this went against what many ancients thought regarding the nature of personality, which most believed was more or less predetermined, and simply gradually revealed itself over time. Polybius’ acute awareness of the human race’s inner failings, along with his deep interest in psychology, also rendered him ever mindful of avoiding succumbing to his own emotions or biases in his analysis. Indeed, the Achaean continuously stresses the need for historians to wrestle with their own natural patriotism and partiality. And as some classicists have rightly observed, he may well be the first Greek historiographer ‘to demand that historians rise above the love of their own cities.’

II

Second, Polybius is worth reading for the sophistication of his multi-level analysis of causation, most notably for his emphasis on the need for analysts to learn how to differentiate between a great power conflict’s prophasis [πρόφασις], its simple pretexts or excuses, and its aitia [αἰτία], its much deeper underlying causes.  When seeking explanations or assigning blame for such dread conflagrations, the political historian must be clear-eyed, scrupulous, and relentless in the pursuit of truth: rejecting parsimonious theories, charily weighing competing explanations, and diving with unabashed relish into the meandering complexities of diplomatic history.  It was this combination of moral even-handedness and sound judgment that so endeared Polybius to just war theorists such as Hugo Grotius, who, in the seventeenth century memorably portrayed him as the first historian to establish clear-cut distinctions between a righteous cause for war and merely a persuasive argument. There is an inherently forensic quality to the study of causation, argues Polybius, with his frequent employment of the medical metaphor — commonplace in Greek historiography since Herodotus — and his suggestions that his work is akin to that of the conscientious physician:

For of what use to the sick is a physician who is ignorant of the causes of certain conditions of the body? And of what use is a statesman who cannot reckon how, why and whence each event has originated? The former will scarcely be likely to recommend proper treatment for the body while the latter, if deprived of the required knowledge, will find it impossible to deal with circumstances. Nothing, therefore, should be more carefully guarded against and more diligently sought out than the first causes of each event, since matters of the greatest importance often originate from trifles, and it is the initial impulses and conceptions in every matter which are the most easily remedied.

He is characteristically blunt and acerbic in his distaste for the academically trivial, griping that if:

…history fails to address questions as to why and how a given event happened, and for what purpose, and whether there was anything unusual about the outcome, what is left is a prize essay without educational value, something that provides short-term satisfaction, but is of no help at all for the future.

Rarely, however, does Polybius provide one, simple, overriding explanation in his quest for understanding. Instead, he points to multiple drivers, has a noted preference for subtly striated interpretations, and lustily embraces complexity. For example: was the Second Punic War the result of Carthage’s attack on Saguntum, a Spanish city allied to Rome, or of its earlier crossing of the Ebro? Was it, perhaps, the long-term consequence of Rome’s own earlier violation of a peace treaty when it opportunistically — and illegally — seized Sardinia and Corsica while Carthage was riven by the vicious inner turmoil of the Truceless War? Or was it simply the inevitable result of ancient hatreds and Punic revanchism, epitomised in the legend of Carthaginian general Hamilcar Barca forcing his young son Hannibal to vow revenge on Rome for his own defeats during the First Punic War? Or perhaps, and more likely, was it a combination of all the above, with some drivers more immediately powerful and impactful than others?

Throughout the Histories, and especially in Daedalean geopolitical situations such as these, Polybius will doggedly present all arguments and explanations and then weigh them together, not necessarily leaning definitively in one direction, yet striving to always present the most valid competing viewpoints. No monolithic theories or crudely parsimonious explanations of tectonic upheavals in international politics for this seasoned historian-cum-statesman. Admittedly, some modern, more hedgehog-like academics in the field of security studies may find this approach frustrating and Polybius altogether too intellectually vulpine for their tastes. Other, more historically-minded, scholars of statecraft will no doubt find Polybius’ approach to be both the more rewarding and more reflective of diplomacy’s kaleidoscopic quality.

III

Third, Polybius is perhaps the most unsparingly practical of all ancient historians, espousing a uniquely symbiotic approach to historical learning and statesmanship. Not only did he view the study of ‘pragmatic’ or political history as an essential prerequisite for any aspiring statesman  but he would later argue all historians, prior to taking up their pens, should have experience in government, and preferably in waging war. Pouring scorn on his more sedate colleagues, who merely ‘spend time in libraries and acquire a great deal of abstract book-learning,’ he reminds his readers that any serious undertaking of political history must be comprised of ‘three branches,’ or lines of effort.

The first is the study of works of history and the collation of the material they contain; the second is the inspection and mapping of inland and coastal features such as cities, battle-sites, rivers and harbours; the third is practical political experience.

There was a special ‘vividness’ in certain historians’ prose — such as Thucydides or Xenophon, for instance —Polybius suggested, that was ‘most likely found only in writers who have taken up the writing of history after gaining direct experience in public life,’ before grudgingly conceding that while ‘it is hardly likely that any one person will have been involved and active in everything,’ a historian should ideally still seek to have ‘personal experience of the most important areas of life, those that affect the largest numbers of people’ ‘The frequency,’ he added, ‘with which we encounter this kind of vividness in Homer proves that it is not an impossible goal.’

IV

Last but not least, Polybius’ concept of symploke [συμπλοκή] —  the study of the interweaving of events — will resonate deeply with contemporary students of grand strategy, already accustomed to scrying the riotous flow of world affairs with the hope of spotting, amid its eddying whirls, underlying currents of cause and effect. The historian notes in the opening to his Histories that with Rome’s rise as the great power arbiter across the Mediterranean, he had witnessed the advent of a new form of ‘universal’ history, one which had forcibly meshed formerly disparate sub-theaters together, and which therefore required the budding historian to take a more synoptic view of geopolitical developments.

Only a century earlier, Aristotle had argued that as history consisted all too often of a simple catalogue of otherwise disaggregated events, it was eternally condemned to remain an inferior genre to poetry, with its unified structure and greater degree of intellectual coherence. Major events in different theatres could certainly be synchronous, he observed, but in a fractured, multipolar world this did not mean they were interlinked. For example, it had become something of a folk tale since at least the time of Herodotus that the battle of Himera (pitting the Western Mediterranean Greeks against the Carthaginians in Sicily) and the naval confrontation of Salamis (involving the Eastern Mediterranean Greeks versus the Persians) had unfolded on the very same day in 480 BC. And yet, Aristotle contended in Poetics, one would be hard pressed to point to both conflicts’ interactive effects, as they had ‘occurred simultaneously without in any way tending towards the same end; in exactly the same way one thing may follow another in succession over a period of time without their producing a single result.’ For Polybius, however, these assertions no longer held true — while the world of his ancestors may have possessed a ‘disseminated’ or ‘sporadic’ character, with ‘no more unity of conception and of execution than unity of place,’ history had now begun to reweave itself, under Rome’s region-straddling shadow, into a more ‘organic whole.’ If a violent storm now erupted in one conflict-lashed corner of the Mediterranean basin, its chill winds would, sooner or later, reach the other.  Indeed, one of the most memorable passages of Polybius’ Histories is that describing the peace conference of Naupauctus in 217 BC, during which the Aetolian ambassador Agelaus vainly exhorts his feuding fellow Greeks to focus their energies on the ‘clouds that loom in the west,’ i.e. the growing Roman threat.

It was time, Polybius argued, for a new approach — one which altogether eschewed silos and ‘partial histories,’ and which also took care to record parallel events across interlocking theatres, which, ‘as points of reference and comparison’ would then allow historians ‘to draw conclusions at a different level.’  In practice, Polybius chose, somewhat ingeniously, to relay historical events Olympiad by Olympiad (a period of four years), then year by year within each Olympiad, before trying to cover the different loci of competition in the same order: Italy, Spain, Africa, Greece, Asia, Egypt — with the constant circumvolution providing the reader with the requisite sense of simultaneity. Polybius’ unique approach to ‘universal,’ or cross-regional, history would be much emulated across the centuries, inspiring figures ranging from the Florentine intellectual Bernardo Rucellai (1448-1514) to the nineteenth-century German historian Leopold Von Ranke (1795-1886).

For therein lies, no doubt, the most intriguing and stimulating aspect of Polybian thought for any student of grand strategy: his clear focus on chains of causation, his close attention to the interconnections between theatres, actions and events, and his refreshing ability to analyse history horizontally as well as vertically. ‘One can get some idea of a whole from a part,’ he observes, ‘but never knowledge or exact opinion.’ Whether you are a practically-minded historian or a historically-minded practitioner (and ideally, for Polybius, one should aspire to be both) you should be prepared to continuously sift through the warp and weft of historical events, with the aim of discerning, amid its jumble of tangled threads, the patterns of cause and effect. In more concrete terms, translating this historically-honed wisdom into actual policymaking requires balancing granular regional expertise with the adoption of a more synoptic view — one which can readily comprehend interactive effects across disparate places and timeframes, as well as the inherent costs and/or tradeoffs tied to the prioritisation of certain military commitments.