Algernon is a given male name which derives from the Norman-French soubriquet Aux Gernons, meaning "with moustaches". It is first heard of in reference to William de Percy, 1st Baron Percy, a Knight from Percy-en-Auge, who accompanied William the Conqueror to England in 1066, and ancestor of the Dukes, and Earls of Northumberland, many of whom bore the name. It was also used as a nickname for Eustace II, Count of Boulogne.