Vincent Van Gogh cut off his entire ear rather than just part of it, newly discovered drawings suggest.
The sketches were drawn by Dr Felix Rey, the physician who treated Van Gogh's wounds in 1888, and discovered in a Californian archive.
The drawings depict the artist's ear both before and after the self-inflicted injury, and show he sliced almost his entire ear off.
Previous claims suggested he had only cut off his earlobe or part of his ear.
The sketches were discovered by Bernadette Murphy among papers owned by Irving Stone, who had been in touch with Dr Rey in 1930.
Her research has also shed more light on "Rachel" - the woman who Van Gogh had handed his severed ear to with the words "keep this object carefully".
The findings suggests Rachel was not a prostitute, as had previously been thought, but a girl who worked as a maid in brothels as well as a cleaner in business premises.
Murphy began investigating Van Gogh after visiting Arles, the artist's home in the 1880s.
Her findings will be published in a new book, Van Gogh's Ear: The True Story.
Coincidentally, a new exhibition which will focus on the artist's mental illness is due to open in the Netherlands this month.
On The Verge of Insanity, which will be housed at the Van Gogh Museum in Amsterdam, will feature the artist's portrait of Dr Rey.
The painter cut off his ear after suffering a mental breakdown. He was found alive by police the next day and taken to hospital.
Van Gogh took his own life in 1890.