Wikipedia has a little bit of info on the etymology, it's quite interesting! > Guillaume de Cahaignes, a French knight who participated in the Norman conquest

Wikipedia has a little bit of info on the etymology, it's quite interesting! > Guillaume de Cahaignes, a French knight who participated in the Norman conquest of England, and lord of what is now Cahagnes, was given Milton in Buckinghamshire and the Sussex village of Horstede (The Place of Horses in Old English). The latter became Horstede de Cahaignes and in time Horsted Keynes