The Third Heaven Conspiracy by Giulio Leoni, trans Anne Milano Appel

When there's trouble in paradise send for the detective Dante Alighieri

As readers' interest in historical crime fiction grows more omnivorous, writers cast around for real-life historical personages to employ as their detective figures. The results are becoming progressively more outrageous - even Groucho Marx has been drummed into service as a sleuth. But there is a certain logic in using the poet Dante Alighieri to solve a baffling mystery, as Giulio Leoni does in The Third Heaven Conspiracy. Born into the lower ranks of the Italian gentry in 1265, he wrote some of the greatest works in world literature, including The Divine Comedy, whose vision of hell is utilised in this novel.

What Leoni has seized on for his atmospheric mystery is the poet's political career. In 1300, Dante was a prior in Florence, wielding some power before he was forced into exile. Leoni opens with a virtuoso set-piece, in which a grumbling Dante is summoned in the night to a grisly murder scene. A celebrated artist has been bound upright in front of the massive mosaic he is working on, his face encased in caustic lime.

Aficionados of this genre might think: so far, so familiar. But Leoni handles his religious sleuth in an unusual fashion. Unlike the customary modern figure clashing with a medieval age, Dante is presented as a man of his time, obsessed with the religious protocol of his high office, bullying his inferiors and disapproving of female sexuality.

Leoni's decision to make his protagonist unsympathetic is an audacious one, but despite our dislike of Dante's boorishness (not to mention his ponderous, self-important speech), we find ourselves drawn to him as he journeys through this vividly realised medieval world.

The Third Heaven, itself, is a secret society whose members all bear a resemblance to animals or birds, and it's clear that they have something to do with the murder of the artist Ambrogio. And what is the involvement of the sinister Boniface, whom Dante describes as "a hypocritical specimen of a pope"?

The best thing about Leoni's book is the fashion in which he effortlessly immerses the reader in a fascinatingly alien world, still very like our own in its political corruption and religious hypocrisy.

The worst thing is the leaden dialogue, which lies flat on the page; perhaps translator Anne Milano Appel could do little to make this aspect take wing. This caveat aside, The Third Heaven Conspiracy is an ornate and vibrant literary pleasure.