At the toughest, most turbulent time of his life, the Post-Impressionist painter was supported by an unlikely soulmate, Joseph Roulin, a postman in Arles. A new exhibition explores this close friendship, and how it benefited art history.

On 23 December, 1888, the day that Vincent van Gogh mutilated his ear and presented the severed portion to a sex worker, he was tended to by an unlikely soulmate: the postman Joseph Roulin.