Soon after Julius Caesar’s assassination in 44BC, a comet was seen streaking across the Italian skies for seven successive days. The soothsayers and astronomers soon agreed that the portent represented Caesar’s soul ascending to the heavens, “there to be received among the spirits of the immortal gods”.

Today, thankfully, we may no longer deify our politicians, but Mary Beard represents the nearest thing in contemporary academe: a semi-deified don and an object of worship, both by the Senate House and by the people. Her new work, SPQR, is probably her most ambitious yet, a magisterial history of Rome which attempts to understand “how a tiny and very unremarkable little village in central Italy became so dominant a power over so much territory in three continents”.

Professor Beard tops and tails her account of the rise of the Roman empire by laying out why she believes its study – to which, she says, she has “given a good deal of the past fifty years of my life” – is still not only relevant, but very important, so giving her own answer to the celebrated Monty Python conundrum: “What did the Romans ever do for us?” Rome, she explains, “still helps define the way we understand our world and think about ourselves”:

After 2,000 years it continues to underpin Western culture and politics, what we write and how we see the world, and our place in it. . . . The layout of the Roman imperial territory underlies the political geography of modern Europe and beyond. The main reason that London is the capital of the United Kingdom is that the Romans made it the capital of their province Britannia . . . Rome has bequeathed to us ideas of liberty and citizenship as much as of imperial exploitation, combined with a vocabulary of modern politics, from “senators” to “dictators”.

She concludes: “Many of our most fundamental assumptions about power, citizenship, responsibility, political violence, empire, luxury and beauty have been formed, and tested, in dialogue with the Romans and their writing.”

The publication of SPQR coincides with another excellent book covering much the same territory, Dynasty: the Rise and Fall of the House of Caesar by Tom Holland, the other contender for the laurel wreath of being Britain’s most widely read and industrious classicist. The two books differ slightly in their aims: Holland focuses on the century-long rise and fall of the Julio-Claudian dynasty, while Beard takes a longer view, from Romulus and Remus right up to the early 3rd century AD. The near-simultaneous release of these books, written in intriguingly different styles, can only sharpen an unspoken rivalry for dominance over the classical world, the modern literary equivalent of the showdown between austere Augustus – who nonetheless had a genius for good publicity and keeping himself in the public eye – and the more flamboyant Mark Antony. In this Actium, however, there are two winners.

Mary Beard is the more academic and measured of the two. Analytical and judicious, she is constantly weighing the archaeological evidence against that of written texts, and she watches the frontiers of the Roman empire with the assurance and authority of a senior umpire calling a wicket. Holland is concerned more with building an engrossing narrative, and in diving deep into the human and biographical forces driving Roman history. He is a witty and skilful storyteller, capable of penning penetrating psychological portraits of the monsters who form his subject: he notes with relish that Caligula is “one of the few people from ancient history to be as familiar to pornographers as to classicists”. He recounts with pleasure his racy tales of psychopathic cruelty, incest, paedophilia, matricide, fratricide, assassination and depravity.

Holland is quite correct that the history of the Julio-Claudian dynasty (that is, the first five Roman emperors – Augustus, Tiberius, Caligula, Claudius and Nero) seems to have “sprung from some fantasy novel or TV box-set”:

Tiberius, grim, paranoid, and with a taste for having his testicles licked by young boys in swimming pools; Caligula, lamenting that the Roman people did not have a single neck, so that he might cut it through . . . Nero, kicking his pregnant wife to death, marrying a eunuch, and raising a pleasure palace over the fire-gutted centre of Rome. For those who like their tales of dynastic back-stabbing spiced up with poison and exotic extremes of perversion, the story might well seem to have everything.

Indeed – though for those who prefer their Rome without testicle-licking, Professor Beard may be the safer choice.

Both books open by considering the Romans’ strikingly unflattering myth of origin. The tale of Romulus and Remus is an odd one with which to celebrate the founding of a great city, involving as it does a rape, an unwanted pregnancy, a bungled attempt at infanticide and a successful fratricide. But as Holland comments, non-Romans “found it all too plausible. That Romulus had been fathered by Mars, the god of war, and suckled by a she-wolf appeared – to those brought into bruising contact with his descendants – to explain much about the Roman character.” As the Byzantine emperor Justin observed of his Roman neighbours, “It is only to be expected that they should all of them have the hearts of wolves. They are inveterately thirsty for blood, and insatiable in their greed. Their lusting after power and riches has no limits!”

Both authors then consider the early kings whose tyrannical excesses led the Romans for hundreds of years to refuse to allow supreme power to remain with any single ruler, and caused them instead to embrace a republican form of government in which supreme power long rested with Senatus PopulusQue Romanus – “the Senate and People of Rome” – the SPQR of Beard’s title.

It is only with the pivotal moment of the rise of Augustus, however, that the mists of mythology clear and both books fully come alive. It is a story so familiar from drama and fiction, from Shakespeare’s Julius Caesar and Antony and Cleopatra through I, Claudius and Caligula to HBO’s Rome – indeed, even the Asterix comics – that it comes as something of a surprise to see how closely the lineaments of the tales we have followed since childhood resemble the hard reality of recorded history.

For Holland, Augustus is the small-town gangster who rises from a relatively obscure background to become Julius Caesar’s adopted son. He portrays a chillingly ruthless figure whose rise to become the first emperor of Rome involved using the murder of Caesar as his springboard into power-gathering a party around him and carefully orchestrating a series of assassinations by his illegal private army of thugs and hitmen, “a harvest of aristocratic heads” that culminated in the bloodiest civil war of antiquity. This reached its murderous climax on the fields of Philippi, where in 42BC he finally defeated Caesar’s enemies, the champions of the Republic, in a battle in which it has been estimated “that a quarter of all [Roman] citizens of military age fought on one side or the other”. Having come to power with the assistance of his partners in the Triumvirate, Marc Antony and Lepidus, he then turned on them and seized absolute power following his victory in the Battle of Actium and the suicides of Antony and Cleopatra.

Beard is more admiring of this mesmerising man who dominated the Mediterranean world for nearly half a century, and admits to remaining baffled by such a complex and contradictory figure. She quotes his 4th-century successor Julian the Apostate, who likened him to “a chameleon . . . a tricky old reptile continually changing colour . . . one minute gloomy and sombre, the next parading all the charms of the goddess of love . . . enigmatic, slippery and evasive”.

The tall and godlike figure we see in his still instantly recognisable, mass-produced statues, industriously distributed around the empire, seems to have borne only a passing resemblance to the real man, who, according to his contemporaries, was a frail hypochondriac who wore platform shoes to mask his shortness, and had unkempt hair, bad teeth, “poor spelling . . . terror of thunderstorms and [a] habit of wearing four tunics and a vest under his toga in the winter”. Among his final words to the friends who assembled at his bedside as he was dying was “a characteristically shifty” quotation from a Greek comedy: “If I have played my part well, then give me applause.”

“What kind of act had he been playing all those years?” Beard asks. “Where was the real Augustus? How Augustus managed to recast so much of the political landscape of Rome, how he managed to get his own way for more than forty years, and with what support, is still puzzling.”

Augustus, widely seen as Rome’s greatest emperor, highlights the problem we have with almost all these towering monsters: do we regard them as “great”, for the way they bestrode the world, bringing with the Pax Romana prosperity and civilisation to the entire Mediterranean region? Or do we see them as primal models of the corruption and depravity that autocracy and tyranny necessarily bring in their wake, as well as being templates for the violence and exploitation of later centuries of European imperialism? The Romans clearly believed in their own mission civilisatrice: as Pliny put it, it was Rome’s destiny “to unite previously distinct powers, to soften patterns of behaviour, to provide a common language to the numerous peoples hitherto divided by their savage tongues, to civilise mankind – in short, to unite the peoples of the world, and to serve them as their fatherland”. Yet the brutality of Roman colonialism was often extraordinary, and the casualties enormous even by modern standards. Julius Caesar’s campaigns in Gaul, for instance, have often been compared to a genocide. “A million people, so it was said, perished over their course,” Holland writes. “A million more were enslaved.”

In both books, the reader is repeatedly struck by the ease with which the very human figures of the Julio-Claudians move from being totally familiar, and motivated by thoroughly modern aspirations and desires, to moments when they suddenly become utterly alien. Beard is especially good on this. From one point of view, she writes, “. . . everything seems reassuringly familiar: there are conversations going on that we almost join, about the nature of freedom or problems of sex; there are buildings and monuments we recognise and family life lived out in ways we understand, with all their troublesome adolescents; and there are jokes that we ‘get’.” One of the great concerns of imperial Rome was immigration and the displacement by war of vast numbers of foreign refugees into its urban centres: these are issues which are still current in politics today. But, viewed through another peephole, the Roman world sometimes appears terrifyingly vicious and alien, as Beard explains:

That means not just the slavery, the filth (there was hardly any such thing as refuse collection in ancient Rome), the human slaughter in the arena and the death from illnesses whose cure we now take for granted; but also the newborn babies thrown away on rubbish heaps, the child brides and the flamboyant eunuch priests.

Holland usually stresses the parallels with the modern world in the orchestrated theatricality of the emperors’ public performances, as well as the degree of international celebrity enjoyed by the Roman royal family. “No household in history,” he writes, “had ever before been so squarely in the public eye as that of Augustus.”

The fashions and hairstyles of its most prominent members, reproduced in exquisite detail by sculptors across the Empire, set trends from Syria to Spain. Their achievements were celebrated in spectacular showy monuments, their scandals repeated with relish from seaport to seaport. Propaganda and gossip, each feeding off the other, gave to the dynasty of Augustus a celebrity that ranked, for the first time, as continent-spanning.

Even their sexual lives can appear proto-modern. Augustus’s daughter Julia is a strikingly familiar figure: after her father divorced her mother, Scribonia, she grew alienated from both her father and her stepmother, Livia, and, like some unhappy child of Hollywood, or renegade royalty, took refuge in frenzied adultery. Yet as the depravity of the Julio-Claudians grows ever more bizarre, we again find ourselves in an alien world: the elderly retired Tiberius turns the entire island of Capri into the Roman equivalent of the Playboy Mansion, where youths from leading families are made to enact scenes from the lives of the gods, “obliged to pose as prostitutes, to hawk for business like the lowest class of sex worker, to perform sometimes three or four at a time”. Nero simulates “criminals being torn to pieces” by binding the objects of his lust to stakes, then releasing himself from a cage, “dressed in the skins of a wild animal”, and performing acts of oral sex on his victims.

If Beard is the considered Augustus of classical studies in this country and Holland the Mark Antony, with one eye firmly on the imperial bedroom, the third member of this literary triumvirate must be Peter Frankopan, whose epic study of East-West cross-fertilisation, The Silk Roads, was published in August. Frankopan, however, is no weak Lepidus: his is a book of dazzling range and ambition which, in its chapters on the Roman empire, illuminates a side of Romanitas that does not emerge in Beard’s and Holland’s more Eurocentric work: the degree to which the Roman empire was funded, softened and to some extent civilised by its eastern and Asiatic provinces. It was here, Frankopan writes, quoting the poet-historian Sallust, that “Roman soldiers came of age . . . learned how to make love, to be drunk, to enjoy statues, pictures and art”. It was, after all, Egyptian grain that fed the empire, Levantine taxes that paid for its monuments, and eastern silks that revealingly wrapped its society woman. And it was, finally, an eastern religion, Christianity, that replaced its ancient gods.

It is also Frankopan who gives us a fabulously apocalyptic vision – absent from these books by Beard and Holland – of the fall of Rome to Alaric’s Visigoths in 410AD, and an even more terrifying visitation from the “seedbed of evil”, the Huns. The picture he paints is a sort of classical version of Mad Max: Fury Road. The Huns, he shows, were creatures from a nightmare: dressed in robes made of field mice skins stitched together, they ate raw meat, “partially warmed by being placed between their thighs”. But it was not just that they were “exceedingly savage”; they looked terrifying, too. The Huns performed cranial deformation on their young, “flatten[ing] the frontal and occipal bones by applying pressure [so that] the head grew in a pointed manner”, as well as “scarring the cheeks of infant boys when they were born . . . They spent so long on horseback that their bodies were grotesquely deformed; and they looked like animals standing on their hind legs.”

These were the men who brought down Rome and ended the glory of the Caesars. At long last, the Romans had met their match – a people even more ruthless, brutal and lupine than themselves.

SPQR: a History of Ancient Rome by Mary Beard is published by Profile Books (£25, 606pp)

Dynasty: the Rise and Fall of the House of Caeser by Tom Holland is published by Little, Brown (£25, 483pp)