Spaniels were first mentioned in the 14th century by Gaston III of Foix-Béarn in his work the Livre de Chasse. The "cocking" or "cocker spaniel" was first used to refer to a type of field or land spaniel in the 19th century. Prior to 1901, Cocker Spaniels were only separated from Field Spaniels and Springer Spaniels by weight. Two dogs are considered to be the foundation sires of both modern breeds, the English variety are descended from Ch. Obo, while the American breed descends from Obo's son, Ch. Obo II. In the United States, the English Cocker was recognized as separate from the native breed in 1946; in the UK, the American type was recognized as a separate breed in 1970. In addition, there is a second strain of English Cocker Spaniel, a working strain which is not bred to a standard but to working ability. Both breeds share similar coat colors and health issues with a few exceptions.
While their origins are unknown, "spaynels" are mentioned in 14th century writings. It is commonly assumed that they originated in Spain, and Edward of Norwich, 2nd Duke of York in his 15th century work The Master of Game introduces them as "Another kind of hound there is that be called hounds for the hawk and spaniels, for their kind cometh from Spain, notwithstanding that there are many in other countries The Master of Game was mostly an English translation of an earlier 14th century Old French work by Gaston III of Foix-Béarn entitled Livre de Chasse.
In 1801, Sydenham Edwards wrote in Cynographia Britannica that the "Land Spaniel" is divided into two types: the hawking, springing/springer and the cocking/cocker spaniel. The term "cocker" came from the dog's use in hunting Woodcocks. During the 19th century the term "cocker spaniel" was used to describe a type of small Field Spaniel, which at the time was also a general term to describe a number of different spaniel hunting breeds including the Norfolk Spaniel, Sussex Spaniel and Clumber Spaniel. While there were no Sussex Cockers or Clumber Cockers, there were dogs known as Welsh Cockers and Devonshire Cockers.]The Welsh or Devonshire were considered cockers until 1903 when they were recognized by The Kennel Club as the Welsh Springer Spaniel.