 All modern thoroughbred racehorses can trace a line back to three foundation sires which were imported to Britain in the late 17th/early 18th centuries and the General Stud Book first published by James Weatherby still records details of every horse in the breed.Gambling on horseraces has been one of the cornerstones of the British betting industry and the relationship between the two has historically been one of mutual dependence.The betting industry is an important funder of horse racing in Great Britain, through the betting levy administered by the Horserace Betting Levy Board and through media rights negotiated by racecourses and betting shops.