Ful wys is he that kan hymselven knowe!
– Geoffrey Chaucer
The Canterbury Tales, The Monk’s Tale. The Monk is drawing the lesson that people should beware of Fortune who loves to overthrow victims in a manner that they least expect. He makes this comment concerning the death of Hercules, who wore a shirt steeped in poison given him by his sweetheart but preferred to throw himself on burning coals rather than die by poison.