King Canute has had a raw deal from history. He took his throne down to the beach in order to show his servile courtiers that not even a king could control the waves (that was in God’s power alone). But, ironically, he is now most often remembered as the silly old duffer who got soaked on the seashore because he thought he could master the tides. When, for example, Ryan Giggs tried last year to use a super-injunction to stop the swell of news about his private life, he was hailed as ‘the King Canute of football’.

For Aloys Winterling, the Emperor Caligula offers another case of the Canute problem. He has generally gone down in history as a mad megalomaniac: so mad that he gave his favourite horse a palace, lavish purple clothing, a retinue of servants, and even had plans to appoint it to the consulship, the highest political office below the emperor himself. In fact (so Winterling argues) his extravagant treatment of the animal was a pointed joke. Caligula was satirising the aims and ambitions of the Roman aristocracy: in their pursuit of luxury and empty honours, they appeared no less silly than the horse.

Caligula occupied the Roman throne for just four years, between 37 and 41 AD. He was the son of the glamorous imperial prince Germanicus (who died in mysterious circumstances in Syria in 19 AD), and spent much of his childhood on military campaigns with his father. Hence his name: although he was born Gaius Caesar Germanicus (and his official title was the Emperor Gaius), the soldiers nicknamed him ‘Caligula’ or ‘Little Boots’, after the mini-military uniform, boots included, in which he used to be dressed – and it stuck. At the death of the elderly Emperor Tiberius, he was eased onto the throne, aged 24, ahead of Tiberius’ natural grandson, who was murdered not long afterwards. The popularity of his father – plus the fact that, through his mother, Agrippina, he was a direct natural descendant of Augustus, the first emperor – provided a convenient veil for what must have been a nasty power struggle, or coup. But another coup soon followed. Four years later Caligula was assassinated, and the throne passed to his uncle Claudius, found, as the story goes, hiding behind a curtain in the palace, so terrified was he in the confusion that followed the murder.

Caligula’s reign may not have started too badly. There was perhaps one of those brief honeymoon periods which regularly accompanied a change of ruler in ancient Rome. In Caligula: A Biography, Winterling points to a range of conciliatory measures in the early months. Incriminating documents relating to treason trials under Tiberius were put on a bonfire in the Forum (though it later emerged that Caligula had secretly kept copies). A system of popular elections for magistrates was (at least temporarily) reintroduced, while generous cash handouts were paid to the people of Rome and to the soldiers. In his first major speech to the Senate, he denounced the unpopular actions of his predecessor and promised he would behave better. The canny senators, suspecting that he might forget his promises, ruled that the speech should be recited annually (it looked like a tribute to the new ruler’s oratory: in reality it was an attempt to hold him to his pledge of good behaviour).

Even so most of the ancient accounts of Caligula’s reign focus on his cruelty, his excesses and (following Suetonius, who wrote the classic biography of the emperor almost a hundred years after his death) his clinical insanity – an unpredictable mixture of fits, anxiety, insomnia and hallucinations. A whole range of stories tell how he claimed to be a god, to hold conversations with Jupiter and to sleep with the moon goddess. He is said to have built a bridge to link his palace on the Palatine hill with the major temples on the nearby Capitoline hill, as if to unite secular and religious power in the state. There is also plenty of talk about his ridiculously extravagant lifestyle (from serving food covered in gold leaf to draping his wife in jewellery that was worth a good deal more than the total fortune of the average Roman senator) and, of course, about his capricious sadism. According to Suetonius, he forced a father to watch the execution of his son and then, later that day, to dine with him at the palace. (Why on earth did the man turn up to dinner? Answer: because he had another son.) He used criminals as food for his wild beasts when beef became too expensive. On one occasion, after recovering from an illness, he insisted that a loyal citizen who had vowed to offer his own life if the emperor survived, should stand by his vow and die.

Modern versions of Caligula in film and fiction have been even more lurid. The most famous is the 1979 movie, funded by Bob Guccione and Penthouse, with a script by Gore Vidal. It starred Malcolm McDowell as a convincingly bonkers young emperor, backed up by a group of A-list actors, including Gielgud and Helen Mirren, who were said to have been unaware of the soft porn enterprise in which they were involved. (Did they think that Guccione was bankrolling serious historical drama?) Much more shocking was the portrayal of Caligula in BBC Television’s 1976 adaptation of I, Claudius. In his novels, Robert Graves had exploited the ancient allegations that Caligula had a suspiciously close relationship with his sister Drusilla. The inventive Jack Pulman, author of the screenplay, went even further. In a terrifying scene that has no source either in ancient accounts or in Graves’s narrative, he has Caligula (John Hurt) take on the guise of Jupiter and cut the baby Drusilla is carrying from her belly and – on the model of some versions of divine gestation and paternity in Greco-Roman myth – eat the foetus. The ‘Caesarian’ itself was not shown on screen, but Caligula’s very bloody mouth was. Deemed too much for American audiences, the scene was cut out of the PBS version of the series.

A few elements of the standard version of Caligula’s excesses are at least partly confirmed by archaeological evidence and the occasional eyewitness account. No certain trace has ever been discovered of the supposed Palatine-Capitoline bridge. But the recovery, sponsored by Mussolini, of two vast pleasure barges from Lake Nemi (one explicitly identified, on some internal piping, as Caligula’s property) gives an idea of the luxury of his court life. They were apparently equipped with hot and cold running water, richly decorated with sculpture and mosaics, and roofed with gilded tiles, almost all sadly destroyed by Allied bombing during World War Two, and not discussed by Winterling (a few remaining fragments are on show in the Palazzo Massimo Museum in Rome).

Caligula’s preoccupation with a high standard of living accommodation is also implied by the philosopher Philo’s wonderfully vivid account of visiting the emperor in 40 AD on an embassy on behalf of the Jews of Alexandria. He was at his ‘garden estates’ (horti) on the edge of Rome, and – according to Philo – the envoys were forced to trail around after him as he inspected his property (‘examining the men’s rooms and the women’s rooms … and giving orders to make them more costly’) and commissioned the ancient prototype of window-glass. ‘He ordered the windows to be filled up with transparent stones resembling white crystal which do not hinder the light, but which keep out the wind and the heat of the sun.’

In the midst of this imperial Homes and Gardens scene, Philo hints at the difficulties of doing business with Caligula and at the autocratic style of his rule. The envoys were careful to bow low to the ground in greeting him, but Caligula’s response was merely to taunt them with sacrilege (‘You are haters of god, as you do not think that I am a god, I who am already acknowledged to be a god by every other nation’); he went on to ask them why Jews don’t eat pork: a question which caused a rival embassy, also seeking to influence the emperor, to laugh out loud. The Jews attempted to say that different people have different habits: ‘Some people don’t eat lamb,’ one Jewish envoy said. ‘They’re quite right, it’s not very nice,’ Caligula replied. By this time he was mellowing slightly, and although the embassy left dissatisfied, the emperor’s parting shot adopted a tone more of pity than anger: ‘These men,’ he said as they went, ‘do not appear to me to be wicked so much as unfortunate and foolish in not believing that I have been endowed with the nature of god.’ It would be hard to miss, in Philo’s indignant tale of this encounter, some of Caligula’s well-known trademarks: ridicule, humiliation, extravagance and whim. But it is some way from the monstrosities that dominate most ancient and modern accounts.

It is now very hard to write a convincing biography of any Roman emperor, even those who have not become mythologised in the way that Caligula (or Nero, or Commodus) has. But Winterling has succeeded much better than most others who have made the attempt. This is largely because he doesn’t share the usual biographical horror vacui which drives writers to tell the complete story of their character from cradle to grave, even where there is no surviving evidence at all. For most Romans that absence of evidence shrouds their entire childhood. So the first chapters of almost any modern life of a Roman are more or less bound to follow the ‘would have’ school of biography: ‘Like most Roman babies, Caligula would have been suckled by a wet nurse/swaddled for six months/potty-trained early’; ‘Like most Roman boys, Caligula would have been taught by a Greek slave/encouraged to learn the techniques of oratory/kept apart from girls’; and so on. Winterling has none of this. He doesn’t invent what we don’t know, but instead concentrates on the evidence there is. The result is a well-founded, and slim, volume.

His main question is: what went wrong? Whatever the murky circumstances of the succession, it appears that the reign started reasonably well, but quickly degenerated first to a stand-off between emperor and Senate, and before long to murder. Why? Winterling’s answer is partly to be found in that story of Caligula’s favourite horse, and in the serious point he believes the emperor was trying to make.

The focus of his book is the dissimulation and hypocrisy that lay at the heart of Roman imperial politics, and had in a sense been the foundation of the governmental system established by Augustus. In making one-man rule work successfully at Rome, after almost half a millennium of (more or less) democracy, and establishing a ‘workable entente’ between the old aristocracy and the new autocracy, Augustus resorted to a game of smoke and mirrors in which everyone, it seems, was play-acting. ‘The senators had to act as if they still possessed a degree of power that they no longer had, while the emperor had to exercise his power in such a way as to dissemble his possession of it.’ As others too have recently emphasised (in particular Shadi Bartsch in Actors in the Audience), the politics of the empire were founded on double-speak: no one said exactly what they meant, or meant exactly what they said. It is no surprise that, on his deathbed, Augustus is supposed to have quoted a line, in Greek, from a comic drama, comparing his own role to an actor’s: ‘If I’ve played my part well, clap your hands – and send me off the stage with applause.’

On Winterling’s model, successful emperors after Augustus were those who managed to exploit the double-speak, and turn it to their advantage; the unsuccessful were those who fought against it. Caligula’s predecessor, Tiberius, ‘never grew into’ the role. He ‘took it all at face value’, refused to master the game of ‘ambiguous communication’, and in the process repeatedly revealed the autocratic reality of imperial rule underneath the carefully constructed democratic veneer of the Augustan system. So, for example, according to the Augustan principles, stable relations between Senate and emperor demanded that the Senate continue to debate issues apparently freely – but always in full knowledge of the outcome desired by the emperor. Tiberius, however, insisted that the Senate decide important issues of policy without making clear to them what his own view was. He then became angry ‘when they reached decisions counter to his wishes’. Ultimately, relations between the emperor and the traditional governing class broke down so badly that Tiberius spent the last decade of his reign on the island of Capri, governing Rome from a distance and through a series of more or less vicious henchmen.

Caligula also resisted imperial double-speak, but – according to Winterling – in a subtly different way. He tried to fight the ambiguity of political communication that had become the norm in the imperial regime and to counter not only its insincere flattery and apparent emptiness, but also its systematic corruption of meaning. That is the message which underlies the story about the man who had vowed his own life if Caligula recovered from his illness. The intention of this public vow, we must assume, was to draw attention to the man’s deep loyalty to the emperor, and so attract a handsome reward for his devotion; it was no indication of the man’s real readiness to die. ‘The explicit wish – for the emperor’s recovery – did not match the unstated wish: to be rewarded for their flattery.’ By taking it at face value, Caligula is ‘outing’ the insincerity, and showing that he would ‘abjure this form of communication’.

The campaign against imperial double-speak turned out to have disastrous consequences. The story of the honours given to the favourite horse already hints at these when we see it not as a sensible cautionary tale, but as an instance of the lunacy it was trying to critique. There was in ancient Rome – as there always is – a grave danger in insisting on the ‘face value’ of communications, however honest it might at first seem. Such insistence can work in two diametrically opposite ways: it can reveal the absurdity of empty flattery, but it can also serve to make the absurd claims of the flatterer seem literally true. To develop Winterling’s argument a little: in Caligula’s world the rejection of coded language and double-speak had the effect of validating the absurd and extravagant claims about imperial power. It didn’t expose the suggestion that the emperor was a god as empty rhetoric or subtle metaphor, and so in a sense defuse the deification. Quite the reverse: if words must always mean what they say, then Caligula was divine.

What is more, the aristocracy was humiliated in the process. There had been an important point to ‘empty flattery’ in the Augustan system. It could sometimes (as the story of the senators requesting an annual recitation of Caligula’s speech shows) be used by the flatterers as a mechanism of control over the object of their flattery. More often the very emptiness of it allowed the senators to play their part in praising the emperor without having to believe all they said. Strip the flattery of its emptiness, and the senators ended up looking ridiculous, as if they were committed to the words they were speaking. It was this humiliation, in Winterling’s view, that soon led to the violent rift between Caligula and the aristocracy – a rift that ended in his assassination.

Caligula: A Biography offers a sharp analysis of political communication in imperial Rome and faces the central question raised by many ancient writers themselves: the question of how language functions under an autocracy. It is an eloquent and compelling study of Roman imperial history, and especially of the difficult relations between the imperial monarch and the traditional aristocracy. Whether Winterling also has the answer to the particular problems of Caligula’s reign and can provide the explanation of its apparently rapid decline into tyranny is another matter.

For a start, he doesn’t tell us – or not very convincingly – why Caligula felt the need to attack the rhetorical conventions of imperial rule in the first place. He is also repeatedly forced to adjust a good deal of unpromising, or even conflicting, evidence to fit his basic scheme. Too often, he takes some bizarre anecdote supposedly illustrating Caligula’s madness and ingeniously reinterprets ‘what actually happened’, to end up with yet another example of Caligula’s resistance to (or exposure of) imperial double-speak and hypocrisy.

Take the story about a commercial brothel established by the emperor on the Palatine, to raise money for the imperial treasury (according to Suetonius). Installing Roman matrons and respectable boys in a lavish suite in the palace, he sent heralds out to invite anyone to come and enjoy them and lent customers money for the fee – at substantial interest. Winterling puts this story together with a passage (selectively excerpted, it must be said) from the History of Dio Cassius, describing the enforced lodging of some leading Roman families in the palace, almost as hostages. After a few pages of rather one-sided argument, the brothel disappears altogether from Winterling’s version, and the story becomes another example of Caligula exposing the insincerity of the aristocracy. In this case, he pretends to take their protestations of friendship seriously and so installs their wives and children close to him in the palace. ‘What actually happened’ turns out to be far away from anything recorded in Suetonius, or even in the (non-excerpted) account of Dio. Rather too far for comfort, in my view.

But we are still left wondering how we should understand the extraordinary tall stories told by ancient authors about Caligula’s crimes. If we don’t believe them to be literally true, and if we cannot rationalise them all into a single model of conflict between emperor and Senate, what sense do we make of them? Here Winterling has another explanatory weapon in his armoury. He rightly insists that the problems of succession define not only imperial history, but also historiography.

Augustus had answers to many of the problems of governing the Roman Empire: from the carefully nuanced – even if hypocritical – balance of power between monarch and aristocracy to his wholesale nationalisation of the Roman army (which for most of the preceding five hundred years had been, in a sense, a private militia acting on behalf of a series of unscrupulous political leaders). But he conspicuously failed to set up a reliable system of monarchical succession. That was partly because there was no recognised Roman principle of inheritance (such as primogeniture). And it was partly due to bad luck: Augustus and his long-term wife, Livia, each had children with earlier partners, but none together. The result was that the Roman Empire came into being with a question mark over who was likely to succeed, and over the centuries the succession was repeatedly fought out by murder, or by allegations of murder (witness the suspicious death of Caligula’s father). As Walter Scheidel has recently shown, the Roman Empire has a bloodier record in the transfer of power than any other monarchy in the history of the world. In fact there were allegations, true or false, that every single one of the first dynasty of Roman emperors was murdered – from the poisoned figs (supposedly prepared by Livia) that were said to have finished off Augustus to Nero’s forced suicide after a military coup deposed him.

Winterling is right to point to the impact of these bloody transitions of power on the written history of the empire. Most senators during most reigns were collaborators (as most people are under most systems of power, however brutal); and when regimes changed they made every effort to reposition themselves, usually by excoriating in speech and writing, in ever more gory detail, the emperor who had been their friend. That writing is the Roman imperial history we have inherited. And it determines our view not only of the brief reign of Caligula, but that of almost every Roman ruler. Even the most hard-headed and cynical of ancient Roman historians are implicated. Tacitus, who devastatingly exposed the corruption of the regime of Domitian (81-96 AD) after the emperor’s death, had himself been a beneficiary of Domitian’s patronage during his reign and had been rapidly promoted by that monster in the Roman imperial honours race.

Just occasionally Roman writers themselves recognised that survival in Roman imperial politics depended on the ability to reinvent oneself at regime change. In the nicest example, Pliny, in a letter written in the early second century AD, told of a dinner party where the conversation among a group of friends turned to one Catullus Messalinus, a notorious hatchet man during the reign of Domitian. ‘I wonder what he would have been doing now, if he was alive today?’ one of the guests asked. ‘He would have been eating here with us,’ another replied. Whatever the ups and downs of double-speak, the fact is that most of Caligula’s senatorial friends and enemies survived his years in power to denounce him after his death; their vitriol is our legacy.