Central to their theory is a phrase Van Gogh wrote to Gauguin: 'You are quiet, I will be too.' They also point to the phrase 'pact of silence' used in a letter Van Gogh wrote to his brother Theo, in which he refers to a request by Gauguin to have his fencing mask and gloves returned to him.
Significantly, there is no mention of the epee which Gauguin is supposed to have thrown in the river Rhone.
He even painted the famous Sunflowers to decorate Gauguin's room.
Gauguin arrived in October and the two started to work together, producing several now famous canvasses.
But, crucially, he almost certainly suffered from a form of manic depression, or what we now call bipolar disease.