Developed from a cross between the King Charles and a Cocker Spaniel, the Cavalier King Charles Spaniels differs greatly from its forebears. Its breeders were trying to reproduce a toy dog similar to those seen in portraits from the time of England's Charles II, who was said to dote on these small dogs. In the 1920's the American, Roswell Eldridge, offered prize money during a Cruft's Dog Show in London, to any person exhibiting Cavalier King Charles Spaniels with long noses. He was looking for dogs similar to those appearing in Van Dyck's paintings of King Charles II and his spaniels. By the 1940's these dogs were classified as a separate breed and were given the prefix Cavalier, to differentiate them from their forebears.

Appearance
The Cavalier King Charles Spaniel is by most measures the largest toy breed: though clearly a lap dog, fully-grown adults tend to fill one rather amply. It is nonetheless quite small for a spaniel, with fully-grown Cavaliers roughly comparable in size to an adolescent of a more conventional spaniel breed. Breed standards call for a height between 12-13 inches with a proportionate weight between 13 and 18 lbs. Unlike most other spaniels, the Cavalier King Charles Spaniel has a full-length tail well-feathered with long hair, which is typically carried aloft when walking.

Character
The breed is highly affectionate, and some have called the Cavalier King Charles Spaniel "the ultimate lap dog". Most dogs of the breed are playful, extremely patient and eager to please. As such, Cavalier King Charles Spaniels are usually good with children and other dogs. A well-socialized Cavalier King Charles Spaniel will not be shy about socializing with much larger dogs. (However, on occasion, this tendency can be dangerous, as many cavaliers will presume all other dogs to be equally friendly, and may attempt to greet and play with aggressive dogs).

However, the extremely social nature of the Cavalier King Charles Spaniel means that they require almost constant companionship from humans or other dogs, and are not suited to spending long periods of time on their own. The Cavalier King Charles Spaniel is the friendliest of the toy group.

The Cavalier King Charles Spaniel enjoy agility, they would classify for the mini dog section.
 

Temperament
The Cavalier King Charles Spaniel in many ways fits the bill as an ideal house pet. It is sweet, gentle, playful, willing to please, affectionate and quiet. The Cavalier King Charles Spaniel is amiable toward other dogs, pets and strangers. Outdoors, its spaniel heritage kicks in, and it loves to explore, sniff and chase. The Cavalier King Charles Spaniel is an eager, affectionate tail-wagger. Lively, outgoing and sporty, these fearless lively little dogs want to please. The Cavalier King Charles Spaniels are intelligent enough to understand what you want and therefore are usually easy to train and respond well to gentle obedience training.

Exercise/Training
The Cavalier King Charles Spaniel needs a fair amount of exercise every day, either in the form of a moderate walk on leash or a romp in a safe area. Playing and obedience are very good types of mental exercise. 15 minutes obedience and playing with your Cavalier King Charles Spaniel will be more useful for the dogs exercise then an hour walk on the leash can provide.

Color
The breed has four recognized colours: Blenheim (rich chestnut on pearly white background), Tricolour (black and white with tan markings on cheeks, inside ears, resembling eyebrows, inside legs, and on underside of tail), Black and Tan (black with tan markings), Ruby (rich reddish-brown all over)
Parti-colors are the colors that include white: Blenheim and Tricolor. Whole-colors have no white: Black and Tan, and Ruby. The Blenheim is the most common colour for the Cavalier King Charles Spaniel, although the others are not rare. If you are wanting to show a Blenheim Cavalier King Charles Spaniel extra points will be given for a rich chestnut dot placed between the eyes on the top of the forehead, called the lozenge. It is rare which makes it desirable for show breeders.

Grooming
The coat of the Cavalier King Charles Spaniel needs brushing every other day. A good nutrition and regular brushing keeps the proper coat of the Cavalier King Charles Spaniel shine and the skin healthy. Bathing doesn’t harm the coat of the Cavalier King Charles Spaniel as long as you use a good quality shampoo that doesn't dry the skin and coat and is formulated for a canine coat. The ears of the Cavalier King Charles Spaniel should be kept clean and regularly inspected as well.