The Sealyham Terrier received its name from the eponymous estate of Captain John Tucker Edwardes located in Haverfordwest, Wales. The retired soldier sought to develop a dog that would specialize in small game and be mainly white in color. To do so, he crossed several strains of terrier, likely including the now-extinct White English Terrier, the Dandie Dinmont, the Fox Terrier, the West Highland White Terrier and the Corgie.
This breed was very popular among the elite in Old Hollywood. Alfred Hitchcock, Cary Grant, Humphrey Bogart, Gary Cooper, Elizabeth Taylor and Jean Harlow all owned Sealyham Terriers. The Sealyham is past its heyday in terms of popularity and is relatively uncommon.