The black and white English Spaniel known as the Holland Spaniel was perhaps the oldest of the colour/varieties. The first solid colour known was black. Later, the small water dog known as the Toy Trawler introduced the black and tan pattern, bringing with it the curly coast sometimes seen even today. The solid red or Ruby variety arrived much later. The Blenheim, originally known as the Italian Spaniel, was developed as a small hunting dog by the Dukes of Marlborough, from whose family palace they take their names.

Cross-breeding with the pug, Japanese Chin and Bulldog allowed the development of the "apple" round head and flat face. Their small size and gentle loyal nature endeared these loving creatures to the English and French and allowed the breed to enjoy immense popularity.

With the fall of the Stuart kings, many of these little favorites followed their masters into excile, but Queen Victoria returned the breed to royal favor. Through the Edwardian era the breed continued its popularity in England.

The Royal Courts and Ducal houses all had their own strains of toy spaniels. The King Charles was one of the favourite subjects of the Victorian artists, and the sixteenth century Italian artists also used toy spaniels to embellish their work.

Prior to 1885, only two varieties were recognized by the English Kennel Club - the red and white Blenheim and the black and tan King Charles. Action was started that year to gain recognition for the reds and tricolors, although it wasn't until 1892 that final approval was given. A newly solid red Spaniel with some white on the head appears in a Van Dyke painting, and the tricolor was probably developed by crossing the red and white Italian Spaniel (Blenheim) and the black and white Holland Spaniel.

By the early nineteenth century the breed had evolved to the present-day King Charles as we know it. By natural selection the face was shortened over a period of time. All four colours were established: the King Charles (black & tan); the Ruby (rich chestnut red); the Blenheim (has a ground of pearly white with bright rich chestnut or ruby-red markings distributed in large patches) and the Prince Charles (tri-colour has tan with markings in black instead of red on a pearly white ground).

World War II proved to be a trying time for the English breeders and many of the kennels were moved out into the countryside so not to be endangered from bombings.

In 1885 a small band of devotees got together to form the Toy Spaniel Club. A sqabble ensued over the official name of the club and an appeal was made by powerful friends to the King himself. His Majesty Edward VII let it be known to the Kennel Club that he wished the Toy Spaniel Club in future to be known by its historic name of the King Charles Spaniel Club. The Kennel Club naturally bowed to his royal wish and the name was officially adopted.