The King Charles Spaniel (also known as the English Toy Spaniel) is a small dog breed of the spaniel type. In 1903, the Kennel Club combined four separate toy spaniel breeds under this single title.

The other varieties merged into this breed were the Blenheim, Ruby and Prince Charles Spaniels, each of which contributed one of the four colours available in the breed.

Thought to have originated in East Asia, toy spaniels were first seen in Europe during the 16th century. They were made famous by their association with King Charles II of Great Britain and Ireland (1630–1685) and have been linked with British royalty since the time of Queen Mary I (1516–1558).

The King Charles Spaniel and the other types of toy spaniels were crossbred with the Pug in the early 19th century to reduce the size of the nose, as was the style of the day.

Historically the breeds that were merged into the King Charles Spaniel were used for hunting. They have kept their hunting instincts, but do not exhibit high energy and are better suited to being lapdogs. The modern breed is prone to several health problems, including cardiac conditions and a range of eye problems.

It is thought that the toy spaniels that eventually became the King Charles Spaniel originated in East Asia, primarily Japan. They may share a common ancestry with the Pekingese and Japanese Chin. Toy spaniels were given as gifts to European royalty.

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