The Twelve Caesars, By Matthew Dennison

Rome's first dozen emperors covered the spectrum of humanity. A vigorous new history restores them to life.

Matthew Dennison is one of those rare marvels, a historical biographer whose work has reached the bestseller lists. He may be known best for his columns, but for those of us working at the sharp end of historical writing he came to prominence for his acclaimed biography of Princess, Beatrice, youngest daughter, confidante – and virtual slave – of Queen Victoria. He went on to approach another woman close to the seat of power. His biography of Livia, wife of the Emperor Augustus, is highly readable, although the paucity of historical detail in her case makes it harder to create a definitive history. Lacking the claustrophobic mother-daughter relationship that carries The Last Princess, the life of Livia is more scholarly than passionate.

For his latest work, Dennison has chosen a larger canvas. Taking as his starting-point The Twelve Cesars by Suetonius, he has built around that definitive text a humorous, intelligent, highly personal stroll through the careers of the first 12 men who ruled in post-republican Rome. This is not a deeply scholarly work: historians down the ages have examined the sources, the geography, the climate, the dress, the social mores and the possible implications of each and every recorded utterance of most of these men (the three who failed in the Year of the Four Emperors, 69AD, are generally given shorter shrift) in considerably greater depth.

Dennison does not attempt to emulate these; he keeps footnotes to a minimum and his extraneous sources are lightly used. Suetonius offered enough titillation, scandal and rumour among the nuggets of likely fact to give any writer scope for comment. What this book does is to put Suetonius in context, and make him accessible to the non-classical reader.

We are reminded throughout that most of these men were succeeded by their enemies, even when those enemies were their relatives, and that history is written by sequential winners, each of whom builds his reputation on the rubble of his predecessor. Octavian (Augustus) and Titus Flavius Vespasianus are almost unique in venerating the men who preceded them, but even Julius Caesar was never allowed to live down a youthful dalliance with the ageing King Nicomedes IV, while Tiberius was accused, among other things, of training small boys to swim behind him and lick at his genitals. As today, sexual proclivities, whether true or not, were used to demonstrate the clay feet of men who styled themselves as gods.

Augustus was more adept at spin: the idealised Roman family of devoted wife, faithful husband and pliant daughter could not have been further from the truth, but few commentators in ancient history (or today) make much of Augustus's philandering. He is examined for his military and political worth while those who cling to the notion of the nuclear family can trace the origin of their fantasy to him. In Dennison's book, they can see it quietly and effectively destroyed.

There were good men among these 12 – Vespasian and Titus stand out as almost uniquely decent in a succession of power-crazed, manipulative, sexually voracious control freaks. Each story is told with humour and personal interpretations of the facts. Then there's the glory of language: Dennison is in love with the English language, and it shows.

The images are vivid and unique: Vespasian curtailed the power of imperial women so that, "Confined to hairdressing, it survives in the ziggurat arrangements of stiff, liquorice-allsort curls which decorate the sculpted busts of first century princesses". You might argue that Caenis, consort of Vespasian, held far more power than that, but you can't help but lose yourself in the prose.

It does come unstuck at times. Octavian/Augustus, for instance, was not, "like Julius Caesar, impatient of those pragmatic deceits by which personal ambition was reconciled to convention". Suetonius, on the whole, ordered his biographies along very stringent lines. Dennison, by contrast, jumps back and forth with dizzying speed. It's not always obvious where we are in a particular life. But it probably doesn't need to be: none of us is reading this because we want to know the history. We'd better return to the ancient sources, or find more scholarly works, for that. We're reading this for the delight of one man's insight into one of the most politically charged, formative periods in Western history.

Dennison himself says his work is "an entertainment, which will have succeeded in its aim if a single reader is inspired to return to ... Suetonius". My copy is dog-eared, tattered and has highlights in four different colours; but, even so, I will return to it afresh after this book. Thus comes success.

Manda Scott chairs the Historical Writers' Association; the latest novel in the 'Rome' series by MC Scott is 'The Eagle of the Twelfth' (Bantam)