This wolf boy, this child of god, this myth

Caspar Hauser David Constantine Bloodaxe £6.95

David Constantine is an odd, extravagant, fantastical, obsessive poet with a special feeling for freaks of nature - odd hermits, for example; or old men who launch themselves off roofs, heads stuffed full of the dreams of Icarus. He has written a book-length study of Holderlin, the 19th-century German poet who was locked away for committing acts of gross visionary excess on the page. Caspar Hauser is the latest addition to his museum of oddities.

Caspar Hauser himself is one of those legendary creatures of the early 19th century, part historical fact, part mythical accretion, of which the mind does not easily rid itself. The depiction of him brutally trying to beat his brains out on a door in Werner Herzog's great film is one of post-War German cinema's most memorable images. Other poets have written about him too - Georg Trakl and, more recently, Clive Wilmer. Now Constantine, a poet from Salford who teaches German at Oxford, a man of slight delicate frame and hair that tumbles down his forehead in tight scribbles of curls who once said: "You can get shut of what's troubling you into the characters of poems", has given us a book-length poem about the boy-legend - part wolf boy, part child of god - in nine fitts.

Caspar Hauser was a boy of no apparent origins who spent the greater part of his life in a darkened room or stable being sustained by - whom exactly? He could utter just one sentence, and that was: "I want to be a horseman as my father was before me." Having emerged into the harsh and unforgiving light of day, he suffered a violent death after only two or three years. Was he murdered at the behest of his parents? Was it in fact a murder at all - and not suicide? Or was the explanation something more exalted altogether? The jurist Anselm von Feuerbach believed that the boy could lay claim to the throne of Baden. Whatever the truth of the matter, a great literature in German grew up around the enigma of his tragic life.

Constantine, having read some of this literature, has played fast and loose with the unstable facts in the case - but who would wish - or expect - a poet to do otherwise? After all, there is the poetry to be faithful to as well.

The poem charts the slow, pathetic progress of this near-dumb and wholly bewildered child towards some degree of self-knowledge - how he is led to Nuremberg and released into the ministering hands of an invalid schoolmaster and poetaster named Daumer. Daumer shows some kindness to his charge, but nothing comes easy. "The sound of music unravels him"; even beauty seems like a booming noise to his over-sensitive ear. And who exactly is the "he" known to others as himself anyway? He never knows.

Each of the principal characters who played a part in Caspar's truncated life of freedom is given a canto to himself or herself - Clara Biberbach, for example, who fell head over heels in love with him; Stanhope, the eccentric English lord who made him his ward.

Each one of them has an opportunity to reflect, often muddle-headedly or self-servingly, upon their unsatisfactory dealings with him.

Constantine has captured marvellously, in a kind of halting, benumbing three-line stanza shape, the half-life of this creature who blinked momentarily into the light of day, only to be brutally snuffed out again for being a threat to the sanity of the kind of vicious, insensitive dullard of which the world continues to be full. Like many writers who deal in murder and bloodlust, David Constantine is mild-mannered in his style.