Standards require this be kept long, with the feathering on the feet a particularly important aspect of the breed's features.The Cavalier King Charles Spaniel and the English Toy Spaniel can often be confused with each other. In the United Kingdom, the English Toy Spaniel is called the King Charles Spaniel, while in the United States, one of the colors of the Toy Spaniel is known as King Charles. The two breeds share similar history and only diverged from each other about 100 years ago. Dogs with whole colored coats were more likely to be affected than dogs with parti-colored coats.