E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Ganelon (g hard).
Count of Mayence, one of Charlemagnes paladins, the Judas of knights. His castle was built on the Blooksberg, the loftiest peak of the Hartz mountains Jealousy of Roland made him a traitor; and in order to destroy his rival, he planned with Marsillus, the Moorish king, the attack of Roncesvallës. He was six and a-half feet high, with glaring eyes and fiery hair; he loved solitude, was very taciturn, disbelieved in the existence of moral good, and never had a friend. His name is a by-word for a traitor of the basest sort.
Have you not held me at such a distance from your counsels, as if I were the most faithless spy since the days of Ganelon?Sir Walter Scott: The Abbot, chap. xxiv.
You would have thought him [Ganelon] one of Attilas Huns, rather than one of the paladins of Charlemagnes court.Croquemitaine, iii.