Hadrian Works, says the road sign at Haltwhistle in Northumberland. It is to direct lorries to a paint factory. This is one part of the country where ancient history is ever present - all because of Hadrian’s Wall. ‘Hadrian’ is a trade name for everything from air conditioning to mineral water. As one who grew up not far from the Wall, next to a Roman fort, Vindolanda, I could hardly avoid being interested in the people who built these things. Having a certain talent for languages, I was early on steered to Latin and Greek and by the age of fifteen, in an era when such specialisation was not frowned on, I spent a very high proportion of my school time on 'the Classics'; the term is not one that I entirely approve of. In the strict sense it means ancient Greek literature from Homer to Demosthenes, i.e. from about the 7th to the 4th centuries BC, and Latin literature from Plautus to Juvenal, from the 2nd century BC to the early 2nd century AD. What the Greeks wrote after Alexander the Great and the Romans after the Emperor Trajan is ‘post-Classical’, not good literature, in the standard judgement.

At Oxford University this point of view dictated the Classics syllabus. Greek History stopped in 323 BC with Alexander’s death and Roman History with the death of Trajan, ‘one of those Romans who looked stupid and were thought to be honest’, as Ronald Syme once put it. What happened after that - after 8th August AD 117 - didn’t count. ‘Modern History’ at Oxford (history there was either ancient or modern, the term ‘mediaeval’ for some reason being avoided) began with Diocletian, in AD 284. What came between was a kind of black hole. It is true that Juvenal was still writing his Satires from a few years after 117 - but these were not all suitable reading for the young anyway. But otherwise, there was no respectable ‘Classical’ literature.

Having got to Trajan’s death, when I took Finals, I badly wanted to know what happened next. (I was pleased to read in A.J.P. Taylor’s autobiography a few years ago that this was his principal aim as an historian. An old-fashioned view, no doubt, but none the worse for that.) Hence when I started a doctoral thesis I plunged into the ‘black hole’. I just missed out on Hadrian, as I was assigned a subject by Ronald Syme that went from Antoninis Pius to Caracalla, AD 138-217, concentrating on the Marcomannic Wars under Marcus Aurelius. The added bonus was that I was awarded a travelling scholarship, which gave me the chance to get to know the Danube and Balkan countries - within limits: the Cold War was at its height, so I didn’t get to Czechoslovakia, Hungary and Romania. But I managed a week in Bulgaria, five weeks in Yugoslavia - then a relatively free, prosperous and apparently united country - and several months each in Germany, France and Italy. The chance to meet dozens of foreign scholars and students, all interested in the second and third centuries AD, was a real eye-opener.

While I was writing up my thesis, my eminent supervisor was often away, and no one else at Oxford seemed able to give advice. My substitute supervisor saw me once in six months, for half an hour, gave me a glass of sherry and urged me to avoid writing ‘will have’ (as in ‘ Pertinax will have become consul in AD 175’). The temptation to occupy my time with something else was too strong to resist. I wrote an article on Marcus Aurelius which was published in History Today, earning me welcome income (£25) and, to my astonishment, bringing a letter from a publisher inviting me to write a book on the emperor. Which in due course I did. But before that I produced another one, Life in Roman Britain; for it so happened that the editor of History Today and of the ‘Life in...’ Batsford series was one and the same person, Peter Quennell. Life in Roman Britain was reprinted a good few times and lasted on for some years after Life in Norman, Elizabethan, Victorian England, etc., had gone out of print. My friend Peter Kemmis Betty of Batsford (alas, no longer with Batsford; but he has started up his own firm, Tempus, just recently) told me that, in the field of history, ancient history books sold on average four times as many copies as those on mediaeval or modern topics. I wonder why this was so - and if it is still the case? It must mean that ‘the general reader’ is attracted to the world of the Greeks and Romans. It may be that the average reader is starved of ancient history at school. This is certainly the case now, when the Greeks and Romans, including Roman Britain, are disposed of to all intents and purposes at primary school.

My first two books were written from 1963-65, when I was a Research Fellow with virtually no teaching duties. Subsequent ones had to be undertaken at weekends, in the evenings or in the Long Vacation. But there has been no going back. In some cases I have been drawn to a subject and felt that I just had to produce my own book on it. In the case of Hadrian, I was persuaded to do it, and held back for some time. There is a school of thought in my profession today which regards the writing of biographies of people from this remote past as a mistake. Some would allow the attempt in the case of only a handful, in effect famous figures who have left behind writings of their own - Cicero, Julian the Apostate and St Augustine (of Hippo). I would add Marcus Aurelius to this very short list, for his Meditations and his correspondence with his tutor Fronto do shed some light on the inner man. But for a whole range of other ‘great men’ - and ‘great women’ too - a biography can’t really get beneath the skin. What do we really know about the thoughts of Alexander the Great or Cleopatra, let alone Crassus or Antigonus the One-Eyed? All the same, there are plenty of monographs devoted to them and to a host of others, which are often cast in the form of a biography.

The point is just this: one has an urge to know what can be known about people who changed the course of history. As for Hadrian, there are some particular puzzles. He was an enigma even to his contemporaries. ‘Changeable, manifold, fickle, born as if to be a judge of vices and virtues, expertly concealing his envious, unhappy and lustful character, immoderate in his urge for display, feigning self-restraint, affability and mildness, disguising his burning desire for glory’ - this was an attempt to sum him up by a 4th century writer. He was something of an intellectual, claiming superior expertise in a range of subjects from architecture to astrology, from etymology to military science. His beard was a novelty. He was the first emperor to wear one. But he didn’t sport the long whiskers that were the badge of the philosopher. Hadrian’s was the well-trimmed beard that had been favoured in classical Athens. Hadrian preferred hunting to Philosophy. His name was his favourite food, huntsman’s’ fare, a game pie with four ingredients, was his tetrafarmacum, the ‘fourfold medicine’. That was what the followers of Epicurus’ philosophy called the master’s teachings. Hadrian was making a joke at their expense.

Philosophy aside, Hadrian adored everything Greek. He acquired this passion early: as a boy he was given the nickname Graeculus ‘ the little Greek’, because of his excessive devotion to Greek literature. In his early thirties he spent a year or so at Athens and even held office there as archon. When he became emperor, he was faced with a series of military crises. After abandoning new eastern provinces on the grounds that Rome couldn’t hold them - which earned him unpopularity - he had to deal with the west first. Further territory was abandoned north of the Danube. Then he unveiled a new frontier policy, marking off the limit of the empire in southern Germany with a great oak palisade - and in Britain by his Wall. A similar artificial frontier was built in due course in North Africa. As much anything else this was a message for internal consumption: expansion of the empire has to stop! Walling out the barbarians was very much a Greek attitude. Once he had settled the west, Hadrian could indulge his craving for Hellenic life. From AD 123-5 and from 128-134 he ranged back and forth though the Greek-speaking eastern provinces, spending more time at Athens than anywhere else. Athens was enormously boosted by his munificence and was designated as the headquarters of a new Commonwealth of all the Greeks, the Panhellenion. Hadrian was in effect reviving an abortive proposal of Pericles from the 5th century BC - and making it work. In many ways he - and the Greek elite - were living in the remote past. Hadrian saw himself as a new Pericles.

The grateful Greeks awarded him the title ‘Olympios’ - which Pericles had only had as a nickname. He was before long identified with Olympian Zeus into the bargain.

An essential feature of the Hellenic way of life had always been ‘Greek love’. The relationship between an older man and a beautiful adolescent youth was regarded by many Greeks as much superior to the marriage bond, as the ‘higher form of love’. Hadrian found a beloved youth, the Bithynian Antinous, and became besotted with him. By the time he went to Egypt in AD 130 the young man was prominent at his side, in spite of the presence of the empress Sabina - Hadrian’s marriage was characterised by mutual loathing. Then tragedy struck. Antinous drowned in the Nile. Hadrian ‘wept like a woman’, declared Antinous to be a god and founded a new city, Antinopolis, opposite the spot where he drowned. Suspicious voices said it was a sacrifice, or self-sacrifice: that Antinous had had to die to save or prolong Hadrian’s life. Others said suicide, which is plausible enough. Antinous had passed the age at which his position as beloved was still honourable. It may be that Hadrian would not let him go, and that Antinous could not bear the strain and the sneering criticism. The deification was at all events an unprecedented step: it had previously been reserved for emperors and their close kin. The Greeks went along with it enthusiastically. Romans in the west were embarrassed and startled.

Life had to go on. Hadrian returned to Athens, to inaugurate the vast temple of Olympian Zeus he had had completed (begun 700 years before and regarded as a white elephant), to serve as the centre for the Panhellenion. He was probably still there when grim news came: a massive Jewish uprising had caused heavy Roman casualties. Hadrian had provoked the rebellion. Unable to believe that anyone in the east could fail to share his desire to become Greek, he had decided to force the Jews to conform. They were ‘forbidden to mutilate the genitals’, as his harsh edict put the ban on circumcision; and Jerusalem, the ruined Holy City, was being rebuilt as a Greco-Roman town, Aelia Capitolina. Inspired by a charismatic leader, Shimon Bar-Kokhba, the Jews actually liberated substantial parts of Judaea for over three years, before they were crushed by the Roman military machine.