There's surely a doctoral thesis to be written about the 21st century's fascination with the Tudor age: Cromwell, Elizabeth I the sisters of kings' mistresses, we can't get enough of the bloody, torturous historical soap opera where hobnobbing with the wrong types could mean a grisly, agonising death.

But it's not only a time of adultery and treason in the highest places; it's also a time of religious schism and great art and literature, of John Knox and Shakespeare. It's a time when playwrights could be government agents, when poets could be spies.

It's long been thought that Christopher Marlowe, author of Tamburlaine and Doctor Faustus, was a government agent in the pay of Elizabeth I's great spy-master general, Francis Walsingham. And that the tavern brawl which precipitated his early death might have been related to his spying activities. These were dangerous times, after all; different factions, jostling for power as the old Queen neared her end (though she was to live another ten years after Marlowe's untimely death), were secretive and ruthless as they sought to outdo one another, and anyone caught up in them, no matter how slightly, could pay with their life.

Ros Barber, an American-born poet now living in England, has researched Marlowe's life and proposed an alternative narrative to the ending we have traditionally read. When this magnificently original novel begins, Christopher Marlowe is across the Channel, in exile, having faked his own death. The tavern brawl is a ruse, to get off his back rival agents who would see him hanged, drawn and quartered for blasphemy and heresy. But his exile is not straightforward: he has left a great love behind, Thomas Walsingham, relative of the dreaded head of intelligence. And more than that, he has seceded his place in the literary firmament. No more Marlowe plays for enthusiastic crowds. No more words from the most feted literary star of the London stage.

Barber tells the story of Marlowe's possible alternative life in iambic verse of ten syllables. This use of the pentameter serves to read more like prose, however, and far from putting off cautious readers, should draw them in. For this is a marvellous reconstruction of a life, told beautifully, with Barber's superb ear not just for the rhythms of the verse but also for the brutality of the times: alliteration is never overused, but informs just as it should ("And fear infects like mould; like fungus, spreads..."); similes fit expertly then expand the sense ("Now dusk descends, and a mist lies on the water like a bride/waiting to be disturbed"); and inner turmoil forever reminds us of our bodily end ("this adopted death", "the endless nights... stitched into a shroud"). Marlowe is in agony abroad, not just homesick for the sights and sounds of London, but also for love, the love that "dare not speak its name".

Because he cannot stay silent though, his friends help him and he carries on writing, only now his works are authored by one William Shakespeare, a real-life individual whom few can remember seeing. Barber has a great deal of fun with this theory, sending Marlowe to Elsinore on one of his agents' adventures, having him write his 'dark lady' sonnets to Walsingham, letting him ponder the meaning of treachery through plays, Julius Caesar and Antony And Cleopatra. The little we know about Shakespeare becomes proof, in Barber's hands, of deliberate obfuscation: we know so little about him because we are meant to know so little. He is not the real Shakespeare, that much we know: Marlowe is.

Throughout this question of authorial identity runs a greater one: the right to be who we are, to be who we want to be. To tell a story in our own words, about our lives, matters deeply to us, because it reflects that basic human right. Barber's Marlowe twists in his exile and anonymity, the worst kind of prison, against forces greater than he is. Perhaps the sense of impotence against all-powerful, unseen forces is really what appeals to us about the Tudor age. If it is, then Barber has captured it perfectly. A truly superb achievement.

Ros Barber

Sceptre, £20

The Marlowe Papers: A Novel In Verse