Peter McCue was a racehorse and sire influential in the American Quarter Horse Association

American Quarter Horse Association

The American Quarter Horse Association , based in Amarillo, Texas, is an international organization dedicated to the preservation, improvement and record-keeping of the American Quarter Horse. The association sanctions many competitive events and maintains the official registry...

 (or AQHA), although he died before the AQHA was formed.
Peter McCue (foaled 1895) was registered in the American Stud Book

American Stud Book

The American Stud Book is the stud book for the Thoroughbred horse in the United States. It was founded by Sanders Bruce, with assistance from his brother B. G. Bruce...

as a Thoroughbred

Thoroughbred

The Thoroughbred is a horse breed best known for its use in horse racing. Although the word thoroughbred is sometimes used to refer to any breed of purebred horse, it technically refers only to the Thoroughbred breed...

, sired by Duke of the Highlands, but his breeder and his breeder's family always maintained that he was actually sired by a Quarter Horse

American Quarter Horse

The American Quarter Horse is an American breed of horse that excels at sprinting short distances. Its name came from its ability to outdistance other breeds of horses in races of a quarter mile or less; some individuals have been clocked at speeds up to 55 mph...

 stallion named Dan Tucker. His dam was a Thoroughbred mare named Nora M, who was a double-bred descendant of the imported stallion Glencoe.