The Cavalier King Charles Spaniel is a small breed of dog usually considered one of the toy dog breeds. It is a small spaniel with substantial silky coat of moderate length, often with a mild wave, and long ears. Four colours are recognized. The breed originated in the 20th century, though has its roots in the older King Charles Spaniel of the Restoration.

History
A young King Charles II with his King Charles SpanielsFor many centuries, small breeds of spaniels have been popular in the United Kingdom. In the eleventh century, in the reign of King Canute, it was illegal to hunt with any dog that could not fit through a gauge that was eleven inches in diameter. Hence, the "birth" of the Toy Spaniel in the United Kingdom. Some centuries later, Toy Spaniels became popular as pets, especially as pets of the royal family. In fact, the King Charles Spaniel was so named because a Blenheim-coated spaniel was the childrens pet in the household of Charles I. King Charles II went so far as to issue a decree that the King Charles Spaniel could not be forbidden entrance to any public place, including the Houses of Parliament. Such spaniels can be seen in many paintings of the 16th, 17th and 18th centuries. These early spaniels had longer, pointier snouts and thinner-boned limbs than today&undefined;s.
Over time, the toy spaniels were replaced in popularity by short-snouted, dome-headed dogs of Asian descent, such as the Pug and Japanese Chin. The King Charles Spaniel was bred with these dogs, resulting in the similar-shaped head of todays English Toy Spaniel breed. The King Charles Spaniel remained popular at Blenheim Palace, home to the Dukes of Marlborough, where the brown and white version was the most popular - resulting in the name Blenheim for that color combination.
In the 1920s, an American named Roswell Eldrige offered twenty-five pounds as a prize for any King Charles Spaniel "of the old-fashioned type" with a longer nose, flat skull, and a lozenge (spot) in the middle of the crown of the head, sometimes called "the kiss of Buddha," "Blenheim Spot," or "Kissing Spot". So, the breed was developed by selective breeding of short-snouted Spaniels. The result was a dog that resembled the boyhood pet of the future Charles II of England ("Cavalier King Charles"), whence the breed derives its name.
Two breed clubs/registries are found in the United States: the Cavalier King Charles Spaniel Club (CKCSC) USA and the American Cavalier King Charles Spaniel Club. The latter club is the breed club of the American Kennel Club.
This breed craves human attention therefore are not suitable to be left alone all day. They are very loyal and love cuddles.

Description
The Cavalier 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, when fully-grown Cavaliers roughly comparable in size to an adolescent of a more conventional spaniel breed. Breed standards call for a height between 29 and 33 cm (12-13 inches) with a proportionate weight between 4.5 and 8.5 kg (10 and 18 lbs). Unlike most other spaniels, the Cavalier has a full-length tail well-feathered with long hair, which is typically carried aloft when walking.

Coat
The breed naturally grows a substantial silky coat of moderate length. Breed standards call for it to be free from curl, with a slight wave permissible. In adulthood, Cavaliers grow lengthy feathering on their ears, chest, legs, feet and tail; breed standards demand this be kept long, with the feathering on the feet cited as a particularly important feature of the breed.
A cavalier&undefined;s coat may be beautiful, but, because it can be long, it is very important to keep it well groomed. This can be done by yourself, or you can hire a professional groomer. If the coat is not properly cared for, the dog will shed quite a bit. Daily brushing is recommended to ensure that the coat does not get matted and that foreign objects, such as grass and sticks, do not become entangled in the feathering. It also should not be bathed more than twice a week otherwise it may cause skin irratation.

Colour
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-colours are the colours that include white: Blenheim and Tricolour. Whole-colours have no white: Black and Tan, and Ruby. The Blenheim is the most common colour, 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.

Temperament
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, dogs of the breed are usually good with children and other dogs. A well-socialized Cavalier 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 KC 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. This breed is the friendliest of the toy group.

Health
Cavaliers can suffer from a number of severe genetic defects. Unfortunately, two possible genetic conditions, mitral valve disease and syringomyelia, can be both severe and very common. If considering a puppy, ask to see its parents heart and eye certificates, and consider seeking a breeder who MRI screens dogs for syringomyelia, to reduce the chance the puppy will have the defects described below. Breeders who breed for health willingly supply health clearances for their breeding dogs, and responsible breeders choose pairings to try to reduce the incidence of all these defects in the breed.