The issues could have been pulled from today’s headlines: the nature of executive power, the defense and security of the homeland, the relationship between domestic and foreign policy. In January of 49 B.C., Julius Caesar crossed the Rubicon River with his army and marched on Rome in pursuit of the consulship, precipitating a bloody civil war that would last nearly two decades and exact a heavy toll on an entire society. The casualty list ultimately included not only thousands of Caesar’s fellow citizens, but the very system of government under which Romans had been living for nearly 500 years. Their beloved republic emerged from the conflict with a new locus of power in the person of theprinceps Augustus—the first emperor of the Roman Empire.

The Rubicon itself was not a site of great geographical importance in Italy—not like the Alps, for example, which Hannibal had famously crossed in his march on Rome at the end of the 3rd century B.C., and the Gauls nearly two centuries before that. But what it lacked in grandeur as a landmark, it more than made up for in legal and political significance. It served as the legal border between the province of Gaul and Italy itself, and therefore as the legal boundary beyond which the Roman commander in Gaul could not pass under arms. Moreover, any Roman commander who wished to stand for civic office—in particular, for one of the two annual consulships, the highest elected office in the Roman Republic—had first to disband his army and enter the city as a private citizen. To cross the Rubicon under arms and march on Rome to seek the consulship was therefore a flagrant violation of multiple legal and political conventions, in a society where law, tradition, and precedent still mattered a great deal.

Caesar’s bold actions can hardly have come as a complete surprise. For one thing, his rivalry with the other great Roman politician, statesman, and military leader of his day, Pompey the Great, had been simmering for years. Their competition for dominance of the Roman political scene had been alleviated by several measures including Pompey’s arranged marriage to Caesar’s daughter Julia and the compact they formed with the financier and aspiring imperialist Crassus to share the spoils of conquest and high office. But Julia and Crassus were both dead by 50 B.C., and now Pompey and his supporters in the Roman Senate stood in the way of Caesar’s ambitions. Something had to give, and Caesar was not one to yield.

But the trouble ran deeper than merely a confrontation between two stubborn, ambitious men. Overweening generals had been challenging the legal and constitutional constraints on their powers for half a century, and one—Sulla, a distinctively Roman conservative revolutionary and revolutionary conservative—had already marched on Rome with his army a generation earlier. In many cases, however, violence wasn’t necessary in order to accomplish one’s political goals. Marius had enjoyed an unprecedented five consulships in succession. Pompey himself had been granted by popular law an extraordinary command against piracy—the “war against terror” of its day, as Rubicon notes—which gave him a command over the entire Mediterranean superseding that of all other provincial commanders. During a year of electoral turmoil and civic unrest in 52 B.C., he had also been granted an unprecedented sole consulship—the only holder for a year of an office designed to be shared by two veto-holding magistrates. It seemed to many, contemporaries as well as later observers, that the decades prior to Caesar’s advance into Italy across the Rubicon witnessed only the last, and hardly the most shocking, in a series of political affronts to Roman law and practice. However strong the historical foundations of the Roman constitution, in practice it seemed increasingly fragile, subject to the ambitions of a few and to the immediate needs of the day.

Caesar’s fateful decision to cross the Rubicon was not only the culmination of these decades of change and upheaval; it was also the catalyst for further years of turmoil, chaos, and uncertainty. The civil war itself did not end with Caesar’s defeat of Pompey at the battle of Pharsalus in 48 B.C., nor did it end with Pompey’s death at the hands of an Egyptian eunuch later that same year. It continued for a full 19 years, under the leadership of Caesar’s adopted son and designated heir, Octavian, and his main rival for power, the general, erstwhile consul, and consort of queens, Marc Antony. Their bloody replay of Caesar and Pompey’s earlier contest, complete with political compacts, arranged marriages, and agreements signed and broken, finally culminated in Octavian’s defeat of Antony at the battle of Actium in 31 B.C. In its wake, Octavian—soon renamed Augustus—fashioned from the ruins of the old republic a new political dispensation, brilliantly contrived to assuage deep-seated Roman hostility to monarchy, that offered the firm hand of absolute rule to a war-weary Roman populace. Even had Caesar wanted to crown himself king of Rome—a subject debated from his own day to ours—he could hardly have envisaged a version of kingship as perfectly suited to its subjects as Augustus did.

The story of the Rubicon, then, is a story of immense historical importance, not only for the Roman people themselves but for centuries of subsequent European and Mediterranean history. It is also a story of intense and vivid drama, full of sex, scandal, intrigue, conspiracy, violence, corruption, and raw ambition. How best to recreate that story in all its import and all its drama? Classicists and academic historians can, of course, take advantage of the extensive contemporaneous evidence from antiquity, which includes not only Caesar’s commentaries and Cicero’s speeches, but numerous inscriptions and coins, as well as later narratives by both Roman and Greek historians. And serious students of the period can enjoy both the powerful prose and the brilliant insights of such seminal works as Ronald Syme’s Roman Revolution, still fresh and provocative over half-a-century after its initial publication. What has been lacking, however, is a well-researched and well-written popular narrative of the decades leading up to the crossing of the Rubicon, as well as its aftermath. In the right hands, the history of these years should be as gripping as any fictional political thriller.

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Enter historian and novelist Tom Holland. Rubicon is a lively, readable, briskly paced account of “the last years of the Roman Republic.” It is also thoroughly grounded in the relevant source material, but it wears its erudition lightly—Holland correctly eschews extensive footnotes and source citations in the interest of maintaining the pace and intensity of his narrative. Students of Roman history will recognize the many threads of evidence woven together into what to the general reader will appear to be a seamless, forward-moving account. That account is essentially chronological, as befits a story of such complexity, punctuated by many successive dramatic episodes. At the same time, Holland makes sure his reader is informed about the basic attitudes and practices underpinning Roman society, from the class system and attitudes toward gender and sexuality to the political system and the legal frameworks of government and empire. Perhaps most importantly for a narrative history, Holland has a full (and often ironic) appreciation for the innate drama of his material, both substantive and anecdotal—offering, for example, an account of the sexual intrigue of the Bona Dea scandal worthy of any supermarket tabloid, as well as brilliant character portraits of major and minor figures in Roman politics, from Crassus to Pompey’s father to Clodia Metelli, “the embodiment of [the] exclusive, if faintly sleazy, allure…of Baiae [a favorite Roman coastal resort]…wine-drenched, perfume-soused, a playground for every kind of ambition and perversion….” Who wouldn’t want to read on?

On the level of popular history, then, Rubicon succeeds brilliantly. Nonetheless, it is fair to ask whether it achieves anything beyond the already significant accomplishment of making a distant and complex part of the past accessible for a general audience. In one important regard, the answer must be no: Rubicon does not advance any new or detailed analysis of why events unfolded as they did. Was the Roman constitution incapable of shouldering the burdens of empire? Did Romans secretly welcome the presence of political and military strongmen, in spite of their anxieties about monarchy and absolute power? Was Caesar so hungry for glory that no existing political arrangements could accommodate his ambitions? What exactly were his ambitions, anyway? Conversely, was Pompey—or even Crassus, had he lived longer—no less a “danger to the Republic” than Caesar? These are only a few of the many important interpretive questions about these decades, and it is unfortunate that Holland, while acknowledging their importance, does not offer a coherent or clearly articulated thesis of his own. His compelling narrative is weakened by the absence of a compelling argument.

Holland accomplishes something else, however, and does so brilliantly. We are living in an age when empire has become a subject of fashionable conversation again, when the example of Rome is frequently invoked in discussions of the nature and exercise of American power. Most such references are anecdotal and uninformed. They take into account neither the power of the Roman example in the framing of the American Constitution, nor the profound cultural and political differences separating a postmodern, nuclear power from a pre-modern, territorially based empire. Holland fully understands both the similarities and the differences. While his story is exclusively about Roman history and makes no pretenses to comparative analysis, he is aware of the provocative parallels. Section headings such as “The War Against Terror” and “Mutually Assured Destruction” signal this to readers, but Holland leaves it up to us to decide what his tale of imperial grandeur and political turmoil has to teach the present day. This reader, at least, often felt that he was reading an extended meditation on American power, refracted through a time far distant yet provocatively close. Rubicon therefore offers not only a gripping account of the Roman past, but an important perspective on the current American moment. The Ides of March may not be so remote from the Ides of September after all.