'Self-portrait with cut ear' by Vincent Van Gogh.

Vincent van Gogh's fame may owe as much to a legendary act of self-harm, as it does to his self-portraits. But, 119 years after his death, the tortured post-Impressionist's bloody ear is at the centre of a new controversy, after two historians suggested that the painter did not hack off his own lobe but was attacked by his friend, the French artist Paul Gauguin.

According to official versions, the disturbed Dutch painter cut off his ear with a razor after a row with Gauguin in 1888. Bleeding heavily, Van Gogh then walked to a brothel and presented the severed ear to an astonished prostitute called Rachel before going home to sleep in a blood-drenched bed.

But two German art historians, who have spent 10 years reviewing the police investigations, witness accounts and the artists' letters, argue that Gauguin, a fencing ace, most likely sliced off the ear with his sword during a fight, and the two artists agreed to hush up the truth.

In Van Gogh's Ear: Paul Gauguin and the Pact of Silence, published in Germany, Hamburg-based academics Hans Kaufmann and Rita Wildegans argue that the official version of events, based largely on Gauguin's accounts, contain inconsistencies and that both artists hinted that the truth was more complex.

Van Gogh and Gauguin's troubled friendship was legendary. In 1888, Van Gogh persuaded him to come to Arles in the south of France to live with him in the Yellow House he had set up as a "studio of the south". They spent the autumn painting together before things soured. Just before Christmas, they fell out. Van Gogh, seized by an attack of a metabolic disease became aggressive and was apparently crushed when Gauguin said he was leaving for good.

Kaufmann told the Guardian: "Near the brothel, about 300 metres from the Yellow House, there was a final encounter between them: Vincent might have attacked him, Gauguin wanted to defend himself and to get rid of this 'madman'. He drew his weapon, made some movement in the direction of Vincent and by that cut off his left ear." Kaufmann said it was not clear if it was an accident or an aimed hit.

While curators at the Van Gogh museum in Amsterdam stand by the theory of self-mutilation, Kaufmann argues that Van Gogh dropped hints in letters to his brother, Theo, once commenting : "Luckily Gauguin ... is not yet armed with machine guns and other dangerous war weapons."

Misunderstood and undervalued ... Self-portrait with Palette c 1894 by Paul Gauguin.

Poor Vincent; he gets no rest. If it isn't a new film or TV drama about the tragic genius who ended his extraordinary life in 1890 by shooting himself, it's a new theory about the "true" story of Van Gogh. According to two German art historians, the artist did not cut off his own ear. Instead they claim he menaced Paul Gauguin in a moment of madness and Gauguin, an accomplished fencer who happened to be carrying his sword, whipped off the ear in hasty self-defence.

Are these scholars by any chance graduates of Heidelberg University's renowned duelling tradition? I can't imagine that Gauguin was a good enough fencer to deliver this surgical wound. He'd have been more likely to hack off Vincent's head by mistake.

It is true that Van Gogh's self-harm at Arles in 1889 is a more mysterious event than you might think. The only full account of what happened was written by Gauguin himself. There are more indirect allusions in Van Gogh's letters to his brother Theo. From all this evidence comes the conventional interpretation that, after he worked hard to persuade his hero Gauguin to come and live in the Yellow House, his would-be artist's colony in the southern French town, Van Gogh couldn't face it when Gauguin decided to leave. He confronted the terrified Gauguin with a razor in the public gardens then hacked off his ear and presented it later that night to a prostitute in a local brothel. Van Gogh himself described his mood as a period of insanity and soon afterwards entered an asylum.

A quick look at the letters reveals how the latest theory has been concocted. As he recovered from his wound, Van Gogh answered a request from Gauguin, who'd left Arles, to send on his fencing gear. The wording of Van Gogh's reply is perhaps odd - he connects a reference to the fencing equipment to a refusal to give Gauguin his painting Sunflowers as a memento. Later he jokes about the fencing equipment as "these terrible engines of war."

I suppose allusions like this could be built up into the theory that Gauguin drew his sword on Van Gogh. But surely in that case even Gauguin wouldn't have had the cheek to demand the Sunflowers as a parting gift? For me the conclusive evidence is probably Van Gogh's Self-Portrait with a Bandaged Ear in London's Courtauld Gallery. It associates his injury with his vocation as an artist and a martyr. Van Gogh displays his bandaged ear in a way that accuses himself, not anyone else.

Gauguin always gets a bad press. His paintings are terribly misunderstood and undervalued. Now he's being fingered for wounding Van Gogh. Yet the passion of Van Gogh makes his self-mutilation a perfectly plausible expression of his character, which fits the intensity and sadness of his poignant works.