Before she became a national treasure, with the TV shows and blogs, Mary Beard was already influential in keeping the ancient world alive in modern thinking. As classics editor of the Times Literary Supplement since 1992, she has ensured many books have been reviewed beyond the narrow confines of scholarly journals. Her own books, combining accessibility with profound knowledge lightly worn, have always had a wide readership. Among other themes, she has explored classical art, Pompeii and the subject of laughter in ancient Rome. Now she turns her attention to the role of the Roman emperor, from the rule of Augustus (31 BC–AD 14) to the death of Alexander Severus in AD 235.

In an engaging prologue, ‘Dinner with Elagabalus’ (Elagabalus was the teenage emperor said to have smothered his guests to death with flower petals), she states that she will be dealing with both ‘down-to-earth questions’ relating to the everyday lives of Roman rulers and more abstract ideas of how they were thought about, both by their subjects and by themselves (‘emperors of the imagination’ is the nice term she uses). First, though, she sets the scene by explaining how one-man rule was reintroduced to Rome. The Roman Republic (509–31 BC) was a victim of its own success. Institutions created for a small city-state were not suited to governing a Mediterranean-wide empire. Military commands covering wide swathes of territory, and lasting for years, brought their holders vast wealth and glory. The gap between the winners and the losers in the senatorial elite became too great. Ultimately, one man had to win.

The subject of succession opens the book proper. The first emperor, Augustus, set up an autocracy while claiming that he was going to restore the republic. Beard is always illuminating on the deceits at the heart of the emperors’ rule. In a series of ad hoc experiments aimed at soothing the touchy dignitas of the senatorial elite and allowing them to serve his new order, Augustus hit upon a formula that would last for over two and a half centuries. The legal right of an emperor to rule was to rest on a vote by the Senate and (notionally) the people. At times this was a strength. Rome was spared the automatic accession of infants and idiots suffered by many monarchies. Yet it was also a potential weakness. Any emperor, provided he had the necessary votes, was as legitimate as his predecessor, no matter how he had come to power. The principate was, as Sir Ronald Syme said, ‘an autocracy tempered by the legal right to revolution’.

Behind this book lurks The Emperor in the Roman World by Fergus Millar (1977). That monumental work homogenised all the emperors into a single bureaucrat, forever hunched over petitions, and established the academic orthodoxy that the emperor was essentially passive. Being the ruler of the known world and the vicegerent of the gods turned out to be an arse-numbingly dull desk job. Although she addresses the subject of emperors ‘on the job’, engaged in tasks such as writing letters, sitting as judges, issuing laws and overseeing finances, Beard thankfully does not seek to make them conform to the so-called ‘petition-and-response’ model. Instead she gives us, with joyful relish, everything that Millar left out. We observe the emperor at dinner (grand affairs or intimate suppers), having sex with wives and concubines (the latter of both sexes), interacting with his subjects at the games, travelling the empire for business or pleasure (to be fair, Millar had a section on this), speaking to his soldiers in peace and leading them in war. The emperor is placed in the physical context of the palace alongside the familia Caesaris, the thousands of slaves and ex-slaves that comprised his household. We find emperors negotiating the ambiguities of their religious position. From their deathbeds, we hear their supposed last words, from the dutiful (‘If there’s anything to do, give it to me’ – Vespasian) and the pitiful (‘Mummy, mummy, I’m being killed’ – Geta) to the scatological (‘Blimey, I think I’ve shat myself’ – Claudius).

The concentration on the ‘emperor of the imagination’ at times leads Beard to over-scepticism about the lived reality. When she claims that a Vestal Virgin’s name on coins minted during Elagabalus’s reign ‘suggests some kind of connection between the two, even if not marriage’, you want to say, ‘oh, come on, Mary, all the ancient sources say he married her, and why else was she on imperial coins with the title Augusta?’ Similarly, her refreshing and unacademic honesty in admitting ‘we don’t know’ occasionally goes too far. On Marcus Aurelius’s Meditations (which she calls Jottings to Himself), Beard states, ‘we have no idea exactly when or why the emperor chose to write down his fairly random thoughts on life and morals.’ Except the second book begins with the words, ‘Written among the Quadi on the River Gran’. And rather than just surmising that Pliny expanded his almost interminable speech of thanks to Trajan when writing it up (by Beard’s calculation, it would have taken over three hours to read it out loud, ‘even at a cracking pace’), we could refer to the letter where he tells us that this was exactly what he did.

These cavils aside, Emperor of Rome is a triumph, one of those very rare books that combines fresh scholarship with popular appeal. Full of original insights, it will free students of the subject from the shackles of the petition-and-response model, encouraging them to think about the figure of the Roman emperor in new and exciting ways. Written in an easy, conversational style (Vespasian’s portraits hint at him being a ‘down-to-earth kind of bloke’; Caracalla was ‘knifed while he was having a pee’), the book will leave the general reader entertained and informed, not just about the history but also about what historians do. Beard is particularly good on visual imagery. An up-to-date further reading section equips anyone wishing to explore deeper with the tools to do so. This is her best book so far.