Empress of Rome: The Life of Livia, By Matthew Dennison

History has been unkind to Livia. Aristocratic wife of Rome's first emperor, Augustus, she was pretty in a mild, Nanny McPhee way, intelligent, discreet, chaste and loyal. Unluckily, the union was childless (although she had two sons by a previous marriage), and she found herself presiding over an extended family of other people's sons and daughters.

This was a great misfortune, for to be a stepmother in the ancient world was to be cast as a bully, a persecutor, even a murderess, who typically would stop at nothing to promote the interests of her blood offspring. When the tragic poet Aeschylus described a reef as being "a stepmother to ships", no Greek or Roman needed an explanation of the metaphor.

Augustus made a great fuss of restoring the old Roman republic and concealed his autocracy behind traditional constitutional forms; but he early determined to found a personal dynasty.

Unhappily, every time he identified a suitable male relative as his heir, a cruel fate intervened. A line of hopeful young gentlemen, one after another, was struck down: the first was Marcellus, Augustus's nephew, who (probably) died of typhoid fever at the age of 20.

The whisper spread that Livia had administered poison. Similar rumours blamed her for the deaths of her younger son Drusus, the emperor's grandsons, Gaius and Lucius Caesar, and even Augustus himself (supposedly she smeared figs on his favourite tree with venom).

Her alleged motive was love for her eldest boy Tiberius, in whose interest she meant to eliminate all competitors for the imperial succession. The idea of Livia as serial killer was given new life by Robert Graves in his historical novel, I, Claudius, and she reached a mass audience in the television series of the book, memorably interpreted by Siâ*Phillips.

The truth appears to be otherwise, as Matthew Dennison convincingly demonstrates in his biography of this much put-upon woman. Reports of poisoning in the Roman empire tended to coincide with epidemics, unrecognised or misunderstood by the unreliable medical science of the day. In some cases Livia was many hundreds of miles away from her putative victims and would have had to hire agents to do the dirty deed for her – an extraordinarily foolhardy risk.

All that we can be certain of is that Livia enjoyed a reputation for probity and traditional values. She seems to have taken care not to interfere in politics, although always on hand to give confidential advice. That Augustus held her in healthy respect is clear from his habit, when he wanted to raise an important matter with her, of writing down his views in a notebook and reading them out aloud rather than speaking off-hand.

The challenge facing the biographer of Livia is the paucity of the literary record. To handle this problem, Empress of Rome tells her story in a series of thematic chapters in roughly chronological order.

Events tend to recur and incidents in the Republican past and the imperial future are imported to explain the culture and society of her day. Readers without a secure sense of the timeline of Roman history may become confused.

That said, this is an engrossing and persuasive portrait of one of history's most influential women. It makes good use of Anthony A Barrett's more detailed study, aimed at the academy rather than the agora.

A few small errors disfigure an otherwise accurate and balanced account; so, Atticus was not "Cicero's secretary", but a multi-millionaire and close friend. The Vestal Virgins were not "eternally virgin"; after serving for a minimum term of 30 years, they were able to return to their families and ordinary life.

Livia was a health fanatic and by the standards of the time lived an extraordinarily long life, dying at 86. She liked to prepare her own medical recipes and by a lucky chance two have survived, one for a sore throat and another to relieve nervous tension.

The ingredients are harmless, and very likely ineffective, but the image of Rome's first lady as family chemist is intriguing.

Perhaps here we find the origin of her mistaken but enduring reputation as poison's queen.

Anthony Everitt's 'Hadrian' is published by Random House USA