The Van Gogh museum in Amsterdam has acquired the only known letter written by Vincent van Gogh and Paul Gauguin, and will put it on show in the autumn as part of a wider exhibition.

The letter is ‘the most significant document written by Van Gogh that was still in private hands’, the museum said in a statement.

The four-page letter was sold to the Vincent van Gogh Foundation for €210,600.

Van Gogh and Gauguin wrote the letter in 1888, about a week after Gauguin went to live with Van Gogh at the Yellow House in the South of France, to work closely together as artistic partners.

‘We have been on an excursion to some brothels a few times and we plan to go back and work there,’ Van Gogh wrote. ‘Gauguin is working on a canvas of the same night café I painted. But he’s putting in people we’ve seen at the brothel. It’s going to be wonderful.’