Spaniel type dogs have been found in art and literature for almost 500 years.  Initially, Spaniels in England were divided among land Spaniels and water Spaniels.  The differentiation among Spaniels that led to the breeds that we see today did not begin until the mid 1800s.  During this time, land Spaniels became a bit more specialized, and divisions among the types were made based upon weight.  According to the 1840 Encyclopedia of Rural Sports, Cockers were between 12 and 20 lb.  At this time, it was not uncommon for Cockers and Springers to come from the same litter.  Even a puppy from a toy-sized lineage could grow to be a Springer.

There is no indication from these early sources that Spaniels were used to retrieve game. Rather, they were use to drive the game toward the guns.

During the 1850s and 60s other types of Cockers were recorded.  There were Welsh Cockers and Devonshire Cockers.  Additionally, small dogs from Sussex Spaniel litters were called Cockers.  In 1874, the first stud books were published by the newly formed kennel club.  Any Spaniel under 25 lb was placed in the Cocker breeding pool.  Therefore, the Welsh Cocker was reclassified as a Springer in 1903 due to its larger size and shorter ear.

The hobby of dog showing began in earnest among Spaniel owners after the Spaniel Club was formed in 1885.  The Springer and Cocker were in the same show class until the Spaniel Club created breed standards for each of the types.  The Kennel Club separated the two types eight years later.  Since then, the Springer and Cocker enthusiasts have bred in the separate traits that they desired, which has resulted in more difference between the two breeds.

In America, the American Cocker Spaniel breed was forming, and the English Cocker began to lose favor.  The two types were shown together until 1936, when the English Cocker received status as a separate breed.  The American Kennel Club granted a separate breed designation for the English Cocker Spaniel in 1946.