... When the stranger had tested Caradoc's valor sufficiently, he spared his life, and, taking him aside, revealed himself to him as his father, the magician; he even explained the details of the trick of substitution that he had played on the elder Caradoc years before.  The young man, not pleased, called Eliavrès a liar, but he felt that he had spoken the truth.  The enchanter rode off at the top of his speed.  The court broke up, and Caradoc hastened home to Brittany and repeated to his supposed father everything that Eliavrès had said.  Isaune did not attempt to deny her guilt, and her husband shut her up in a tower of stone... (A Study of Gawain and the Green Knight, Kittredge, 1916)