The Sealyham Terrier is a rare Welsh breed of small to medium-sized terrier that originated in Wales as a working dog. It is principally a white-bodied, rough coated breed, developed in the mid to late 18th century by Captain John Edwardes at Sealyham House, Pembrokeshire.
Following the First World War, it surged in popularity and was associated with Hollywood stars and members of the British Royal Family. Its numbers have dropped significantly since then, with the breed listed as a Vulnerable Native Breed by the Kennel Club; an all time low was recorded in 2008 when only 43 puppies were registered in the United Kingdom. This decline has been blamed on an influx of foreign and designer breeds, and the Sealyham's reduced usefulness as a working dog.
The Sealyham surged in popularity after the First World War in the UK and the United States. Within the Hollywood film industry, the Sealyham became a fashionable dog to own by the Hollywood elite.