The abnormally large heart of a hater

The morning after Byron's death from fever in the bleak Greek marshlands of Missolonghi, his corpse was laid out for examination and hacked apart like a carcass in a butcher's shop before being stitched up again. In the course of the autopsy, it was discovered that the poet's liver was diseased - the predictable legacy of a lifetime's unbridled boozing - and that his heart was abnormally enlarged. But the oddest discovery was that the sutures of the dead man's skull had fused together, a phenomenon normally observed in those who have expired in extreme old age. When the big sleep beckoned him on 19 April 1824, George Gordon, Lord Byron, legendary Lothario, revolutionary martyr and only begetter of Childe Harold and Don Juan, had just turned 36.

Into the brief span of his furious life, "wicked George" had packed not merely the lives of many men, but the experience and aspirations of a whole generation, whose darkest fantasies he was doomed to enact and epitomise for posterity. His sexual appetite was prodigious and omnivorous. Androgynous in appearance and bisexual in bent, he seized every opportunity the world afforded him to gratify his lust with men and women, boys and girls, regardless of nation or station. Desire, for Byron, was nothing if not democratic: he was as happy humping a tuppenny whore as tupping an Italian countess, and as apt to bugger a shepherd boy in Albania as a choirboy in Trinity College, Cambridge. The ensuing bouts of venereal disease and plagues of piles he bore with stoic resignation as the Devil's dues.

Taboos were there to be broken, however catastrophic the consequences for himself and those dearest to him. Byron's love for Lady Oxford did not prevent him from attempting to force himself on his paramour's 11- year-old daughter, Charlotte. And no power on earth could deter him from consummating his fatal passion for his half- sister Augusta. Fortunately for Byron, the sexual hypocrisy of the age conspired to keep the secret of his widely shared taste for young children. But when his estranged wife Annabella threatened to make public his devotion to sodomy and incest, he was left with little choice but to settle for exile and the realisation that he would never see his beloved sister or his little daughter Ada again.

"What I get by my brains," he wrote to Douglas Kinnaird, "I will spend on my ballocks - as long as I have a tester or a testicle remaining." Byron's compulsive lechery (or sex addiction, as it would doubtless now be diagnosed) was only the most flagrant manifestation of his lifelong thraldom to what Benita Eisler calls "the body's imperatives". From the pain and shame of the badly deformed foot with which he was born he could never escape, perceiving in his disfigurement a satanic sign of election, the curse of Cain which set him apart from his kind. His plump mother Catherine bequeathed him a predisposition to corpulence that tortured his vanity and compelled him to endure starvation diets of hard biscuits and soda water in order to sustain his fashionably wasted Romantic image. To placate his hunger pangs Byron constantly chewed mastic, a gum resin distilled from the sap of pine trees, or gnawed his nails down to the quick in a vain attempt to consume the flesh that fettered him. Only swimming granted him respite from his bondage: wherever he found himself, Byron headed straight for the nearest river or sea and swam, sometimes for hours on end, delighting in the weightless liberty denied his limbs on land.

Benita Eisler's spellbinding biography spares us none of her subject's least endearing qualities. By his own admission a "great hater", Byron vented most of his misanthropy in misogyny. Not surprisingly, given his own anorexic obsessions, the sight of a woman eating repelled him, but not half as much as a female display of intelligence: "I am still living with my Dalilah, who has only two faults, unpardonable in a woman - she can read and write," he wrote to his friend Hobhouse. Children fared little better: "I abominate the sight of them so much," he once observed to Augusta, "that I have always had the greatest respect for the character of Herod."

The virulence of both these remarks is more than a little mitigated by their teasing wit, but the wry smile they provoke freezes when one reflects on the countless emotional wrecks Byron left in his wake. Of his adult female victims, such as Lady Caroline Lamb and Countess Teresa Guiccioli, it could at least be said that they knew what they were letting themselves in for. Less easy to dismiss from the mind is the letter addressed in a painstaking childish hand to "Caro il mio Pappa" by Byron's illegitimate daughter Allegra. In it the four-year-old infant begs him to come and take her to the local fair. Byron never replied and did not visit the child. Within a few months Allegra was dead.

It is the measure of Eisler's brilliance as a biographer that Byron's charisma survives her exposure of his monstrous flaws intact. The deeper she dives into the murky sources of his genius, the less we are disposed to moralise and the more we are inclined to stand in awe of what his demons drove him to create. Byron was impelled by a nameless desperation to fill the "craving void" he always felt at the core of his being. For a long time losing himself in sex was enough to keep the darkness at bay, but in the end only poetry could do the trick. Poetry was for Byron "the lava of the imagination whose eruption prevents an earthquake". Every rhyming line was at once an act of exorcism and an expression of the awesome power he acquired through language: "He is the absolute monarch of words," Annabella wrote to her friend Lady Barnard, "and uses them, as Bonaparte did lives, for conquest."

As Benita Eisler makes plain, the human cost of Byron's becoming the self-styled "Napoleon of rhyme" was immense, both to himself and to all who were fated to love him. It would be pure cant to claim that his verse redeemed the havoc that he wreaked, but it is hard to think of anything better to say in the face of Byron's poetic achievement and its colossal impact on European literature, music and painting. Instead, like Byron himself when confronted with the Medici Venus in the Uffizi:

We gaze and turn away, and

know not where,

Dazzled and drunk with beauty,

till the heart

Reels with its fullness; there -

forever there -

Chain'd to the chariot of

triumphal Art,

We stand as captives, and

would not depart.