Rugby got its name in Saxon times. It was first mentioned in the Domesday Book in 1086 as a small farming settlement then called "Rocheberie". One theory is that the name came from the Anglo-Saxon "Hrōceburh" = "Rook fort", where Rook may be the birds or may be a man's name. There is another theory that it is derived from an old Celtic name "Droche-brig" meaning "wild hilltop". Viking influence in the area changed the ending to the Old Norse "-bý"; in 1200 it was spelt "Rokebi". The name later evolved into "Rokeby", and by the 18th century had become "Rugby".