There is an article in the current New Yorker, that I've been meaning to tell you about. Van Gogh's Ear, the Christmas that Changed Modern Art.
Based on a German book by reputable German academics, it says that Gauguin was quite the swordsman and went around with a sword often--and that HE cut off the ear...perhaps while defending himself with a sword. Evidently the cut was too clean to have been done by Van Gogh, people don't self-mutilate themselves that way and there are subsequent letters between the two men that imply that this is what happened.
So Gauguin ran off to Tahiti, became the first "primitive" painter and influenced Picasso with this style. And thus "the Christmas that changed Modern Art". Hmmmmm.