Lord Byron, described by EH Coleridge as "de facto if not de jure a naturalised Italian", was at pains to produce a faithful translation ("word for word and line for line") in his excerpt from Canto five of Dante's Inferno. The translation, "Francesca of Rimini", is this week's poem, but if it leads you back to the magnificent original, all the better.

Byron's work on Canto five, and his other Italian literary projects, were inspired by his young mistress, the Countess Teresa Guiccioli. Like Francesca, Teresa was a native of Ravenna, bound in a marriage of convenience to an undesirable husband, and illicitly in love. As for Paolo and Francesca, shared reading was an erotic spur to the relationship between Byron and Guiccioli.

Matthew Reynolds, in his recent fascinating study, The Poetry of Translation: From Chaucer and Petrarch to Homer and Logue, points out the connection between Byron's desire to be faithful to his girlfriend and to Dante. It's one of several intriguing connections. Dante's text (one Byron had, of course, previously visited in the first Canto of Don Juan) now offered to embody a far more personal and un-ironical story. It would permit impassioned self-disclosure, not only through the persona of Francesca, but through Dante's own ambivalent commentary.

For all his aspiration to fidelity, Byron cuts Dante's exposition altogether, so we lose the stunning imagery of the second circle of hell, with its whirling, lightless storm-winds buffeting like helpless birds the souls of those who, in life, could not control their lust. He even omits the first stanzas of Francesca's speech. The rhyming is usually deft, but the syntax often pays the price in convolution. The sentence in lines 7/8 (more simply translated as "Love, that excepts no one beloved from loving") is painfully inverted and suffers an awkward line-break. The repetitions of "yet" (line nine) suggest metrical padding as much as rhetorical intensity.

The tougher, sharper sounds of Byron's translation are not simply the result of the different sonorities of English, or the scarcity of feminine endings. They are related to interpretation. Byron, for example, hardens Dante's "doloroso passo" to "evil fortune": Dante's "desio" becomes the more emphatic "strong ecstacies" (the adjective "strong" occurs twice in a fairly short space of time). In Dante's text, Francesca names dispassionately the author/book responsible for the lovers' fall: "Galeotto was the book and he who wrote it." Byron omits Galeotto and substitutes, "Accurséd was the book and he who wrote it." Later, in the penultimate line, "smote" seems needlessly fierce. Even when Francesca talks, the poem has a forceful and slightly masculine tone.

Byron is an immense poet, combining the best of Augustan wit and intellect with the best of sensuously and politically charged Romanticism. For me, he is by far the outstanding Romantic, and he is as readable and relevant today as ever. The flaws in "Francesca of Rimini" do not diminish him. This is an occasional poem, as well as a translation, and it's foolish to demand that it be comparable with his original poetry, lyric or epic. However, the work is extremely interesting for the light it throws on poetry-translation itself, and the complexity of the relationships involved. A translation is never less than a transformation – and it may be, for the translator, self-revelation.

Taking the rough with the smooth, the reader can enjoy "Francesca of Rimini" as a poem in its own right. The personal touches – the infidelities, if you like – are not slips, but planned insurgencies, and part of the poem's tough vitality. And when Byron risks using feminine endings (surely associated in his mind with comedy and irony) there is pleasure for the ear, as well as a little humour ("the long-sighed-for smile of her"). The concluding lines have a sense of dramatic fatality that is hard to resist. Even the harsh "smote" earns its place by contributing to the rich alliterative music.

Francesca of Rimini

"The Land where I was born sits by the Seas

Upon that shore to which the Po descends,

With all his followers, in search of peace.

Love, which the gentle heart soon apprehends,

Seized him for the fair person which was ta'en

From me, and me even yet the mode offends.

Love, who to none beloved to love again

Remits, seized me with wish to please, so strong,

That, as thou see'st, yet, yet it doth remain.

Love to one death conducted us along,

But Caina waits for him our life who ended:"

These were the accents uttered by her tongue.—

Since I first listened to these Souls offended,

I bowed my visage, and so kept it till—

'What think'st thou?' said the bard; when I unbended,

And recommenced: 'Alas! unto such ill

How many sweet thoughts, what strong ecstacies,

Led these their evil fortune to fulfill!'

And then I turned unto their side my eyes,

And said, 'Francesca, thy sad destinies

Have made me sorrow till the tears arise.

But tell me, in the Season of sweet sighs,

By what and how thy Love to Passion rose,

So as his dim desires to recognize?'

Then she to me: 'The greatest of all woes

Is to remind us of our happy days

In misery, and that thy teacher knows.

But if to learn our Passion's first root preys

Upon thy spirit with such Sympathy,

I will do even as he who weeps and says.

We read one day for pastime, seated nigh,

Of Lancilot, how Love enchained him too.

We were alone, quite unsuspiciously.

But oft our eyes met, and our Cheeks in hue

All o'er discoloured by that reading were;

But one point only wholly us o'erthrew;

When we read the long-sighed-for smile of her,

To be thus kissed by such devoted lover,

He, who from me can be divided ne'er,

Kissed my mouth, trembling in the act all over:

Accurséd was the book and he who wrote!

That day no further leaf we did uncover.'

While thus one Spirit told us of their lot,

The other wept, so that with Pity's thralls

I swooned, as if by Death I had been smote,

And fell down even as a dead body falls."

March 20, 1820.