Aprudent but brooding second-in-command, he had to endure a long, anxious wait before he finally took charge. He began his reign, AD 117, with a controversial withdrawal from Iraq: too soft, said the imperial hardliners. A bloody insurgency, and the persistent threat of a rival power with deep roots in the Middle East, prompted him to cut Roman losses and redeploy the occupying legions. Peace with the Parthians still left him in charge of a 60-million-strong swathe of Europe, western Asia and north Africa.
His writ ran (to use their modern names) from Newcastle to Cairo; from Lisbon to Jerusalem; from Algiers to Brussels. From the border security system in remote Britannia that he supervised in 122, and which makes his name at least familiar to all, to the forests of Turkey and the waters of the Nile, this soldier- son of a Spanish-Roman clan spent half his time in office visiting the distant outposts of the empire. For 15 years, his slick PR machine celebrated peace and order across these realms in stone, coin and scroll. Then he unleashed a punitive campaign of massacre and expulsion against his Jewish subjects after a revolt in 132. Pretty often, he made it across to Greece: his cultural inspiration, his spiritual home, and the source of his trademark intellectual's beard.
So where, when he found himself at the empire's heart, did Publius Aelius Hadrianus – the Emperor Hadrian – go to think through the policy and tactics of mighty Rome? To the spot where I stood last Friday, on a baking July day, in the Tiburtine hills.
Visitors to the hauntingly evocative site of Hadrian's Villa – 20 miles east of Rome, on the outskirts of modern Tivoli – aren't strictly supposed to step across the colonnaded circular pool on to the island in the middle of the so-called "Maritime Theatre". In reality, this is the most intimate, least theatrical corner of a vast leisure and office facility that covered 120 hectares. But Dr Alessandro La Porta, the archaeologist who directs the site, briskly shifts a barrier. We step over the water across a late-Roman stone bridge (the original two were wooden, and retractable) into the remains of the emperor's private apartments on this compact disc of land. Here, a clever, complex and uneasy man retired to shape the strategy that governed most of one continent and large parts of two more.
This was the still point of his ever-turning world. Today, the sun roasts and the cicadas sing, but peace reigns here. Dr La Porta points to the ruins of a private bathroom and en-suite WC. From the Tyne to the Tigris, who else in the empire enjoyed that? Elsewhere in the villa grounds – in the gargantuan sauna facilities of the Great Baths, the Dubai-dimensioned open-air banqueting hall of the Golden Square, the lake-like courtyard pool of the Pecile – imperial super-size does matter. But here, and in various other nooks, the villa reveals a global governor who relished privacy and even solitude.
Thorsten Opper has curated the British Museum exhibition Hadrian: Empire and Conflict, which opens later this month – a far-reaching reappraisal of the Emperor's life and times, which explains my presence here in Tivoli, and the current media urge to seek the elusive man behind the semi-mythical wall-builder. He points out that the villa "isn't all about size and symmetry and scale. It's a different way of impressing people – not just cold monumentality". This fantasy estate charms as well as awes. The "Canopus" – a shaded rectangular pool, flanked by statues to represent the far-flung marvels of the empire, from crocodiles to caryatids – has a dinky half-domed pavilion for discreet private dining at one end.
Many specialists deduce that the Canopus commemorates not just the empire, as a sort of theme-park of must-see attractions, but Hadrian's relationship with his lover Antinous. He was the Greek youth from Bithynia, in modern Turkey, whose suspicious death in 130 propelled the emperor into a scandalous, empire-wide cult of mourning. Did he drown in the Nile, as the official version went? Or did Hadrian, worried about his waning powers, force or cajole the youth into a ritual sacrifice to appease the gods? Dr La Porta hopes that current excavations near this spot may eventually uncover Antinous's tomb.
No one in the Roman world would have bothered for a moment about Hadrian having a recreational boyfriend. Anthony Everitt, the biographer of Cicero and Augustus who is now working on a life of Hadrian, agrees with the academics that ancient culture had no concept of "homosexuality" as such. Still, he stresses that "it is clear that there were men who had a more or less exclusive and lifelong bent for sex with other men – among them, the emperor Trajan and his successor Hadrian".
Thorsten Opper's book, to accompany the exhibition, does describe Hadrian as "gay" – but mainly, he says, "not to have to talk around it and be Victorian". Whatever terminology we now prefer, Hadrian's off-the-scale reaction to the loss of a toy boy struck many contemporaries as unseemly grief. For Elizabeth Speller, the classicist and author, whose book Following Hadrian traces the emperor's routes around his domains, and unlocks the meaning of his travels, this orgy of remembrance "armed his detractors and severely damaged his reputation".
Yet, as always in the Roman world, the personal quickly became political. Greek-run cities (always Hadrian's favourite locations) vied to set up glamorous statues of Antinous, and so curry favour – and win patronage – with the CEO back in Rome. "Sycophants did this on their own inititiative," says Opper. "This way, Greeks can show their loyalty to Rome, by celebrating one of their own. This is how Roman rule works."
By and large, and with the great exception of the Jews, this self-interested give-and-take – flattery and fidelity in one direction, protection and funding in the other – worked well. Elizabeth Speller counts among Hadrian's greatest legacies "the idea – and in many ways the reality – of a peaceful empire through co-operation, not threat and violence".
As for Antinous, Opper believes that "there must have been a deep emotional bond" between emperor and favourite, although Speller stresses that "the sort of relationship Hadrian had with his beautiful boy was very much more a Greek phenomenon than a Roman one". Meanwhile, the emperor's frosty dynastic marriage to his empress, Sabina, carried on its long, loveless course. Dr La Porta once had a Mexican visitor who asked him the best spot at the villa to propose to his girlfriend at sunset. Hadrian advised the Roccabruna tower, with its panoramic views of the estate. She said yes. That sort of marital romance would have baffled Hadrian – and most upper-class Romans, too.
At the villa, perhaps, Hadrian could grieve for Antinous without inhibition, just as he had quietly sought pleasure here as well. In her much-loved if over-romanticised 1951 novel Mémoires d'Hadrien (written partly in a hotel outside the villa gates), Marguerite Yourcenar calls the Canopus "the tragic architecture of an inner world". Often, in this grand public space, you do catch a glimpse of a vulnerable private face. So it's suitably impressive, and touching, when Dr La Porta heroically leads me in the blazing noon through this beyond-extravagant home and HQ. You catch the contradictory style of a ruler who wielded total power but also, like the sceptical Greek-style intellectual he claimed to be, could wish to shun it too.
The villa has around eight kilometres of subterranean passageways, many wide enough to drive a chariot down. Mostly, they allowed the huge workforce of slaves, soldiers and artisans to go about their tasks unseen; but their boss might use some, too. In the underground "cryptoporticus" – dank and cool even in this heat – you sense the presence of an imperial showman who also loved secrecy.
In spite of its peerless value and spine-tingling atmosphere, Hadrian's Villa also seems, for all its drama and grandeur, slightly shy. A modest 300,000 visitors arrive every year, though a development plan aims to boost that by a third. On one snowy winter's day, Dr La Porta tells me, only a solitary studious German came. At the end of today's tour, though, the villa's dynamic custodian has a word of advice for the British Museum. Next time they plan a Roman blockbuster show, could they please launch it in May or October?
Magical as it is, the villa raises as many questions about its many-faceted constructor as it answers. Peacekeeper or warmonger? Philosopher or propagandist? Idealist or pragmatist? The truth, of course, is that the first term never rules out the second, and that the balance changes, day by day, over the two decades of his reign. Elizabeth Speller views him as the emperor who breaks out of the "nice or nasty" schoolbook mould of Roman history (a bow for Augustus, boo for Nero, smile for Claudius). He was "the first ancient ruler to move beyond caricature". For Opper, "Each generation and each individual needs to find his or her own Hadrian".
This appropriation of his image has gone on for centuries. Back in the centre of Rome, we climbed the sinister spiral ramp that, after his death in 138, bore Hadrian's funeral procession into the heart of his mausoleum – now, after a Christian makeover, known as the Castel Sant'Angelo. Atop its great Roman drum stands a Renaissance palace built by the popes and rich in showy frescoes. In one room, painted for Paul III in the 1540s, a splendid life-sized Hadrian gestures with his left arm out of the window, straight at the Vatican and the dome of St Peter's. This lot are my true heirs, the gesture says. Hadrian, who, if he ever thought about Christians, might have written them off as yet another bunch of pesky Jewish troublemakers, would have gasped at the papal presumption.
Depending on their opinions of imperial aggression, the Victorians either saw a wise pragmatist who – as in the fortification from Tyne to Solway Firth – fixed the governable limits of Rome, or else an arty dilettante whose refusal to go out and conquer opened the door to the decadence ahead. To Yourcenar, writing after the pan-European trauma of the Second World War, Hadrian looked more like a cultivated broker between rival peoples and creeds. Her melancholy man of wide horizons even admired his hardy British tribes, and predicted a future "Atlantic world", governed from the West.
Opper himself perceives a crafty strategist at ease with the arts of war as much as peace. He envisages a ruler who showed off his Hellenic learning as a political ploy to bind the Greek-led provinces even closer to Rome. The most famous statue of Hadrian, in Greek philosopher's robes, now stands revealed as spin: the head was fixed to a separate body. For Opper, Hadrian built his wall not just as a bulwark against "barbarians", or even as a benign symbolic frontier and gigantic piece of installation art. (You are now entering the Roman Empire; please drive your cart carefully; sorry, Scottish banknotes not accepted.) Rather, this network of forts, barriers and roads might have served to isolate and separate the restless natives. The same people, after all, would have lived on either side. Last year, Opper witnessed the effect of Israel's Separation Wall on the West Bank. That partition, like the Berlin Wall, set him thinking about the purpose of such obstacles: "Who tilled the fields under Hadrian's Wall? What did they think of that? We should at least contemplate the idea that it's about dissecting tribal territory and exerting control."
At the other boundary of his power, Hadrian the tolerant multiculturalist provoked the Jews by building a pagan shrine above the ruins of the Temple of Jerusalem – destroyed after the earlier revolt, AD 70. In the 130s, his merciless suppression of the popular rebellion led by the messianic guerrilla chief Simon bar Kochba – "son of the star" – left more than half a million dead. In the aftermath, he wiped the name of Judaea off the map, Ahmadinejad-style. Henceforth, the land would be "Syria Palestina".
Does the modern notion of racial "anti-Semitism" have any relevance here? It's "certainly not correct", says Opper: the salient point is that "the Jews, like the Christians, could not accommodate the cult of the emperor". So the usual Roman tolerance of local deities abruptly ceased. For Anthony Everitt, "there was little in imperial Rome analogous to contemporary racism". Hadrian's near-extermination of Judaea "was the fate Rome invariably meted out to those who refused to march under its yoke". The refusal of Jewish monotheism to compromise with pagan norms, Speller underlines, meant that Roman "carrot and stick" business as usual would not work. Whatever the motives, the Jewish people had no deadlier enemy until the Third Reich. Still, almost 1,900 years later, the words of the Talmud curse Hadrian.
At the fringes, brute force talked. At the heart of empire, spin and spectacle prevailed. Visit the Pantheon in Rome's tourist-clogged centre, and Hadrian's PR genius still casts its spell. Its seventh-century conversion into a church helped ensure the Pantheon's status as by far the best-preserved of all the great Roman buildings. Even filled with tourists on a summer afternoon, its coup de théâtre still astonishes. The perfectly engineered 43m dome show-cases what Opper calls Rome's "concrete revolution" in construction could achieve. And, as the sun falls at ever-changing angles on sumptuous coloured marbles through the 9m aperture at the crown, the Pantheon's non-stop light-show makes for dazzling, near-Hollywood special effects.
But this temple of all the gods also lauded the emperor and his predecessors. It was a shrine to Roman as much as divine power. So much for the celebrated self-effacement of the inscription on the entrance. It fibs that "Marcus Agrippa [who had commissioned a previous building on this site] made this". He didn't; Hadrian did, as everybody knew at the time. Imperial vanity could take the form of modesty. He would have liked the fact that people in Newcastle refer not to "Hadrian's" but to the "Roman" Wall.
The Pantheon proves how much the emperor enjoyed a lovely dome. As we stroll past the domes of the baths complex at the villa, Alessandro La Porta reminds me of a well-known anecdote. Once, before he succeeded Trajan, Hadrian is supposed to have tried to tell the celebrity architect Apollodorus how to improve a design. "Go and draw your pumpkins," the prickly builder reputedly replied. Those "pumpkins" were not squash but Hadrian's beloved domes.
According to this story, Hadrian waited many years and then found an excuse to execute the architect – even if untrue, a sign of his reputation for a long, grudge-bearing memory. Yet the tale seems to reveal his genuine interests, too. As Elizabeth Speller says: "He wasn't just a patron. He wrote; he designed; he thought." Later, those silly "pumpkins" sprouted throughout the Christian and then Muslim lands. From Rome to Istanbul, Washington, DC, to London's St Paul's (and even the British Museum's reading room), Hadrian's hemispheres dominate the skylines of the world.
Hadrian's empire fell, although his canny fix of the succession over two generations ensured another golden age under Marcus Aurelius – whom he talent-spotted. The city he founded beside the Nile to remember Antinous has vanished under the sands. Yet his ideal of a stable imperium – Greek culture, Roman clout – helped inspire Byzantium and the kingdoms that descended from it. And, from Tyne to Tiber, he remains the most visible of Roman emperors, his dreams and demands fixed in turf, brick and stone.
On the evening of my visit to Tivoli, I watched the monks of the Shaolin Temple in China mix dance and martial arts in the choreographer Sidi Larbi Cherkaoui's Sutra – one of the events performed, near the Great Baths, as part of the Hadrian's Villa summer arts festival. Our ghostly host would have applauded the monks' fusion of grace and force; the kinship between the power of art, and the art of power. That Hadrian understood. And, as the audience wandered out past the quiet waters of the Pecile, their path lit by flickering torches, we all knew that this private man can still put on quite a show.
Hadrian: Empire and Conflict runs at the British Museum from 24 July to 26 October; Hadrian's Villa, Bagni di Tivoli, is currently open daily from 9am to 7.30pm. Boyd Tonkin stayed at the Hotel Romae, Rome (www.hotelromae.com), courtesy of the Italian Tourist Board, London