The Cavalier King Charles Spaniel of today is descended from the small Toy Spaniels seen in so many of the sixteenth, seventeenth, and eighteenth century paintings by Titian, Van Dyck, Lely, Stubbs, Gainsborough, Reynolds, and Romney. These paintings show small spaniels with flat heads, high set ears, almond eyes, and rather pointed noses. During Tudor times, Toy Spaniels were quite common as ladies' pets, but it was under the Stuarts that they were given the royal title of King Charles Spaniels.History tells us that King Charles II was seldom seen without two or three spaniels at his heels. So fond was King Charles II of his little dogs, he wrote a decree that the King Charles Spaniel should be accepted in any public place, even in the Houses of Parliament where animals were not usually allowed. This decree is still in existence today in England.

 Today's Cavalier is directly modeled on its royal ancestors but this did not happen without the effort of an American fancier, Roswell Eldridge. Mr. Eldridge traveled to England in the early 1920's hoping to buy two spaniels. He was unsuccessful, finding a diversity of type and none of the "old type", particularly the head type he desired. Employing Yankee ingenuity and determination, Roswell offered prizes of twenty-five pounds to the best male and best female of the "old type" exhibited at Crufts each year.  The motivator worked; interest was generated among breeders to revive the original spaniel.

In 1952, the first Cavaliers were sent to America and a national breed club was formed soon after, but because of the small numbers of Cavaliers they did not gain full breed recognition for 40 years. January 1, 1996 saw the Cavalier King Charles Spaniel enter American Kennel Club competition as the 140th recognized breed.